Praxis Archives – Page 136 of 181

Fred Hoyle: pioneer in nuclear astrophysics

Fred Hoyle, the great cosmologist, nuclear astrophysicist and controversialist, was born 90 years ago in the beautiful county of Yorkshire in the north of England. Hoyle’s first science teacher was his father, who supplied the boy with books and apparatus for chemistry experiments. By the age of 15 he was making highly toxic phosphine (PH₃) in his mother’s kitchen, and terrifying his young sister with explosions. In high school he excelled in mathematics, chemistry and physics, and in 1933 won a place at Cambridge to study physics.

CCEnuc1_07-05 — Later in life Hoyle seldom worked at a desk in a faculty building, preferring a comfortable armchair at home. Image: St John’s College.

On arrival at Cambridge he immediately demonstrated his fierce independence by telling his astonished tutor that he was switching from physics to applied mathematics. The future nuclear astrophysicist foresaw that Cambridge mathematics rather than laboratory physics would give him the right start as a theorist. The country boy displayed an astonishing talent at mathematics, even by the highest standards of the university. He skipped the second year completely, yet graduated with the highest marks in his year. That soaring achievement won him a position as a research student in the Cavendish Laboratory, where Ernest Rutherford held the chair of experimental physics. By the 1930s Rutherford had created for Cambridge the greatest nuclear physics laboratory in the world.

Hoyle identified Rudolph Peierls as a supervisor. Peierls, a German citizen and son of a Jewish banker, had studied quantum theory under the pioneer Werner Heisenberg. In 1933 Peierls and his young wife had escaped the anti-Jewish practices of the Nazi regime; they arrived in Cambridge via Stalin’s Russia. Peierls won a one-year fellowship from the Rockefeller Foundation, and by the time Hoyle tracked him down he had just returned from spending six months in Rome with Enrico Fermi. Peierls immediately set Hoyle the task of improving Fermi’s theory of beta decay, published in 1934. This led, in 1937, to Hoyle’s first research paper, “The generalised Fermi interaction”.

In 1938 Paul Dirac, who had won the Nobel prize in 1933, became Hoyle’s supervisor because Peierls had left Cambridge for a permanent position in nuclear physics at the University of Birmingham. Just one year under Dirac’s silent tutelage enabled Hoyle to produce two papers in quantum electrodynamics, both of them masterpieces.

The impending 1939-1945 war curtailed Hoyle’s career as a theoretical nuclear physicist. In January 1939 he read of Irène and Frédérick Joliot-Curies’ discovery that the fission of uranium by neutron bombardment produced a fresh flood of neutrons. The nuclear physicists in the Cavendish Laboratory immediately realized that a chain reaction could be used to create a nuclear bomb. Hoyle foresaw that war research would drain the UK universities of scientists and mathematicians. Wishing to avoid being drafted for weapons research, he changed his research interest to theoretical astronomy and offered his services to the nation as a weather forecaster. The British authorities declined this suggestion. Instead he found himself engaged in radar countermeasures for the war at sea, a field in which he worked with great distinction that was never publicly recognized.

CCEnuc2_07-05 — B²FH – Margaret and Geoffrey Burbidge, Willy Fowler and Hoyle – admire a steam engine presented to Fowler on his 60th birthday in 1971. Image: Donald D Clayton.

In late 1944 the US Navy convened a secret meeting in Washington for the US and UK to share knowledge of radar research. Hoyle was one of two UK delegates. Outside of the meeting he used his time productively. He flew out to the US west coast to meet Walter Baade, one of the greatest observational astrophysicists of the 20th century. Baade introduced Hoyle to papers that he had missed during his war work, about the extremely high temperatures in supernovae. Baade taught him that a supernova is a nuclear explosion triggered by stellar collapse: “Maybe a star is like a nuclear weapon!” was how Baade put it.

Hoyle returned to England via Montreal, his itinerary allowing him to visit the Chalk River Laboratories. This Canadian facility had played host to British research on nuclear weapons since 1942. From a former Cavendish Laboratory contact, Hoyle learned some of Britain’s nuclear secrets first-hand. What particularly amazed him was how far the measurements of energy levels in nuclei had progressed. Hoyle now made an important connection: what would the nuclear chain reactions look like in an exploding star?

The post-war period

At the conclusion of the war in Europe, Hoyle walked out of his job as a radar scientist (he could have continued if he had wished), and returned to Cambridge as a lecturer. He immediately turned his mind to nuclear reactions in massive stars with central temperatures of around 3 x 10⁹ K. Astrophysicists had long known of the two stellar reactions that synthesize helium from hydrogen. Hoyle, following suggestions by his hero, Arthur Eddington, now asked himself if helium could be processed to the heavier elements via chain reactions. He studied tables giving the natural abundances of the chemical elements, picking up an important clue from the marked increase in abundances around iron, the so-called iron peak. From his solid grasp of nuclear physics and statistical mechanics he convinced himself that the iron nuclei were synthesized in stars at very high temperatures. He set himself the task of working out how stars do it.

CCEnuc3_07-05 — Left to right: R V Wagoner, Fowler, Hoyle and D D Clayton at Caltech in 1967 shortly before a move to Cambridge and Hoyle’s Institute of Theoretical Astronomy. Image: Donald D Clayton.

He quickly became frustrated at the lack of data on nuclear masses and energy levels. Then, one afternoon in the spring of 1946, he bumped into Otto Frisch. Frisch had recently returned to the UK from Los Alamos, where he had worked on nuclear fission aspects of the Manhattan Project. Frisch directed Hoyle to a declassified compilation on nuclear masses that the British authorities had found in occupied Berlin. Drawing on these data from the wartime atomic-weapons programmes, he now worked alone in St John’s College (rather than the Cavendish Laboratory), searching for the answers to the origin of the elements from beryllium to iron.

A single page in a notebook he had first started in 1945 captures the moment when Hoyle cracked this problem. The notebook has a series of reactions, commencing with ¹²C capturing ⁴He, and concluding with Fe. Hoyle treated the problem as one of statistical equilibrium. For example, he wrote down a chain reaction connecting ¹⁶O and ²⁰Ne in the following manner: ¹⁶O + ⁴He^→_←¹⁹F + ¹H, ¹⁹F + ¹H^→_←²⁰Ne + hν. The double arrow symbol he used ^→_← is to indicate that these reactions are occurring in equilibrium, with the action being read from right to left as well as left to right.

Using statistical mechanics, Hoyle calculated the proportions of each isotope that would arise under equilibrium conditions. This is not explosive nucleosynthesis, but a more mundane steady-state alchemy in the cores of red giant stars. Hoyle assumed, correctly as it turned out, that rotational instability and stellar explosions would release the heavier elements inside the star back to the interstellar medium. His scheme neatly matched reality, as its predicted distribution of the different elements corresponded well with their abundance in the natural environment. But there was barely a ripple of interest from the scientific community when Hoyle published his findings in 1946. At that stage he was far ahead of his time in applying nuclear physics to stellar interiors. In the 10 years following publication the paper received just three citations.

One spring afternoon in 1953 a young postdoc, Geoffrey Burbidge, gave a seminar in Cambridge that changed nuclear astrophysics forever. He described the proportions of chemical elements in a peculiar star (γ Gem) that his wife Margaret had just observed. The composition of this star seemed bizarrely different from that of the Sun. The rare earths, from ⁵⁷La to ⁷¹Lu, were spectacularly over-represented: in γ Gem ⁵⁷La has an abundance 830 times greater than in the Sun. The Burbidges appeared to have discovered a star with nuclear reactions taking place on the surface.

The results greatly excited Willy Fowler of Caltech who was in Cambridge as a Fulbright professor. He already knew of Hoyle’s work on synthesis through the iron peak. Now he introduced himself to the Burbidges saying that his particle accelerator in the Kellogg Radiation Lab could accelerate protons to the energies found in solar flares. He exclaimed: “Geoff, the four of us should attack the problems of nucleosynthesis together.”

Soon after the seminar Fowler and Hoyle joined up again at Caltech. Hoyle had a problem on his mind. His synthesis through to the iron peak started with ¹²C. Where had the ¹²C come from? Not from the Big Bang – that made only hydrogen and helium. The synthesis of elements with atomic masses 5 and 8 in stellar interiors was already known to be impossible because there are no stable isotopes with those masses. In the absence of these light isotopes to form a stepping-stone, how could three ⁴He become ¹²C? Calculations suggested that anything synthesized from three alpha particles (⁴He) would be absurdly short-lived. And there the matter rested until Hoyle goaded a reluctant Fowler into action.

One of Fowler’s associates, Edwin Salpeter, had found an enhanced energy level in ⁸Be that lasted just long enough to react with an alpha particle and make the prized ¹²C. However, when Hoyle looked at the nuclear physics more closely, he realized that the ¹²C resulting from Salpeter’s scheme would immediately react to ¹⁶O. However, in a flash of inspiration Hoyle tried to make Salpeter’s triple-alpha process work with an enhanced level in ¹²C. To his amazement he found that if the newly made ¹²C had a resonance at 7.65 MeV the reaction would proceed at just the correct rate.

Hoyle crashed into Fowler’s office without so much as a “by your leave” and urged him to measure the resonance levels in carbon. The experimentalist wasn’t going to embark on a quest that would take many weeks just because an exotic theorist from England asked him to. But Hoyle persisted and Fowler eventually relented. Hoyle had already returned to his teaching in Cambridge by the time Fowler’s group completed the experiment. They did find the resonance at 7.65 MeV, a discovery that Fowler found absolutely amazing. “From that moment we took Hoyle very seriously indeed,” he later said, because Hoyle had predicted a nuclear-energy level entirely on the basis of an anthropic argument.

The Burbidges, Fowler and Hoyle – “B²FH” – now embarked on an enormous research programme to account for the origin of the elements in the entire Periodic Table. The Burbidges brought the observations to the collaboration, Fowler the nuclear data, and Hoyle and Geoff Burbidge many of the calculations (on hand-cranked machines). Their encyclopaedic paper, always referred to as B²FH, ran to 108 pages, appearing in Reviews of Modern Physics in 1957 (B²FH 1957). It has received 1400 citations, which is very high for a paper in astrophysics. It remains a key paper, which set out the physics of several different mechanisms of nucleosynthesis, including the explosive pathways in which supernovae build the elements beyond the iron peak. The paper led to a lifelong friendship between Fowler and Hoyle, both of whom made many further contributions to nucleosynthesis. Fowler was deeply disturbed and disappointed when Hoyle did not get a share of the 1983 Nobel prize, which went to Chandrasekhar and Fowler.

Fowler strongly supported Hoyle’s plans for an Institute of Theoretical Astronomy in Cambridge. This opened in 1968, with nuclear astrophysics at the heart of the programme. Hoyle used the institute as a platform to re-establish British expertise in all branches of theoretical astronomy. By example he pulled the subject out of the doldrums, inspiring a string of distinguished visitors and a legion of graduate students. His research papers (there are more than 500) show he was wrong more often than he was right. That did not trouble him at all. Among the papers in the “right” class, those on nuclear astrophysics still stand as a towering achievement of central importance to astrophysics.

40 great years of the Rencontres de Moriond

From 5 to 19 March, 400 scientists from the four corners of the world gathered in La Thuile to discuss fundamental questions in high-energy physics and astrophysics, during four distinct one-week meetings. This was the 40th Rencontres de Moriond – an event that has grown from being a gathering of around 20 friends in 1966 to an annual institution for scientists everywhere.

CCEren1_07-05 — Méribel 1974. It was traditional at the Rencontres de Moriond for participants to enjoy an afternoon picnic on the ski slope.

In the early 1960s, scientific meetings in which theorists and experimenters discussed questions of mutual interest were rare. Even rarer were meetings in which participants of all ages talked to each other on an equal footing, in a climate insulated from day-to-day problems and far removed from the usual laboratory environment.

In 1965, Jean Tran Thanh Van, a young researcher at Orsay, decided to organize an unusual scientific meeting for January 1966. The subject itself – electromagnetic interactions – was not particularly unusual, but the organization was. The meeting was held in the French Alps in a group of chalets, with no catering help or assistance, few of the visual aids one associates with such meetings and, most importantly, without any telephone contact with the outside world. Tran Thanh Van was helped in this groundbreaking initiative by five colleagues: Bernard Grossetête, Fernand Renard, Michel Gourdin, Jean Perez Y Jorba and Pierre Lehmann.

This was not a conference or a school, but a gathering (“rencontre”) of minds. The name of what became a series of meetings reflects this original motivation. Held in Moriond village, the very first of the Rencontres de Moriond was a resounding success. The 20 participants included theorists and experimenters of all ages, from France, Italy (Frascati) and Germany (DESY). The time was well filled with fruitful but relaxed discussions, culinary experiments, skiing, and evenings spent listening to music performed by the scientists themselves.

CCEren2_07-05 — A packed Les Arcs conference room (La Coupole) in 1981.

The Rencontre was unusual in another respect. Half of the participants and organizers were young researchers, but their views and contributions were as significant as those of the senior members. At Moriond, all participants were equal, and none were more equal than others. Happily this tradition persists today.

For the past 39 years the meetings have not been held in Moriond, but they still take place in the mountains! The content has changed continuously, but the underlying Moriond spirit has taken on a life of its own, much to the surprise of Tran Thanh Van. Those original chalets used in 1966 soon became too small and the Rencontres moved to Courchevel, at the Hotel des Neiges, then wandered from hotel to hotel before finding a temporary home in Meribel in 1970, at the Lac Bleu hotel. Gradually, the Rencontres de Moriond became known as the annual fair of the high-energy physics community. Participants would go their separate ways, conduct their own research, then return to the annual Rencontres to show their latest work, find new collaborators and exchange ideas – and then continue their trek to new horizons. A core membership of more than 80 physicists began to meet annually.

In 1969, Tran Thanh Van felt that it was time to apply the idea of bridges within his discipline to bridges between disciplines. As a result, 1970 saw the addition of a biology meeting (founded by cell biologist Kim Tran Thanh Van) to the particle-physics meetings.

An evolving institution

During the decades that followed, the Rencontres gradually changed in character. From a one-week meeting, devoted essentially to one subject in high-energy physics, it expanded into a two-week conference with two basic topics in particle physics – electroweak and hadronic interactions – and a topic in biology. It became an annual “happening”, followed by physicists and biologists worldwide. It was a place to announce new discoveries, to discover the new directions that researchers were taking, and to forge new friendships and collaborations.

CCEren3_07-05 — Toasting the top quark discovery after presentations by both the CDF and D0 collaborations in 1995.

The Rencontres de Moriond became an institution, but the underlying motivation remained intact. Theorists mingled with experimenters; young researchers (postdocs and PhD students) were encouraged to present their work and talk with senior researchers as with colleagues and friends; even the most outrageous ideas had their place. The Rencontres were often the place for young scientists to present their first serious papers before a prestigious international audience, and a place to meet and listen to individuals before there was even a hint that they would one day win a Nobel prize.

Times changed, the pressure to publish rose and the number of participants grew, but the original convivial spirit of the Rencontres was an invariant from year to year. The early afternoon breaks were invariably devoted to skiing (for beginners and experts alike), but this never stopped the science. Tourists would often wonder who those strange people were, stopping on the pistes to talk about some recondite subject using an esoteric vocabulary, pausing to draw diagrams in the snow, and getting so involved in an arcane discussion on a ski lift that they would almost forget to get off.

Although science was always on our minds, on or off the snow, there was time to talk of other matters, to change the world, to make and listen to music. The scientific community includes a large number of excellent amateur musicians of all kinds, from singers to pianists and violinists, who would often show their skills after dinner around the bar. Sometimes a popular science talk would be organized for the general public of the resort, and these talks were always well received.

Science knows no barriers: a proton is a proton, in Switzerland, America or Russia. But the post-war world was a labyrinth of frontiers and walls, and the Rencontres de Moriond played a part in changing this stifling climate of political confrontation between the East and the West. Every effort was made to help and encourage Russian (and more generally Eastern European) scientists to come to the Rencontres, both to display their considerable scientific expertise – often unrecognised – and to learn about the latest advances in the West. This was a new and different kind of multidisciplinary work, which many years later would find an echo in the Rencontres du Vietnam. The annual Rencontres in the Alps was a peaceful haven where the best minds of hostile, inward-looking nations could meet, talk, exchange ideas, push back the frontiers of their discipline and dream of a happier future.

Changing times

As the 1970s drew to a close, participants at the Rencontres found themselves increasingly attracted by subjects such as atomic physics and astrophysics, which were beginning to encroach on the domain of high-energy physics. The Rencontres had begun as a forum for exchanging ideas in frontier science, and now, true to this spirit, Tran Thanh Van recognized that it was once again time to broaden the scope of the meetings.

In 1981 the Rencontres de Moriond Astrophysique was born. It ran in parallel with the now traditional high-energy and biology meetings, and was an annual event devoted to the study of the infinitely large. The Rencontres de Moriond had become a true interdisciplinary institution, where specialists in distinct disciplines could confront their very different views of the universe. There were accelerator experimenters, observers, theorists in particle physics, cosmologists and even experts in galactic evolution.

During its 40 year lifetime, the Rencontres de Moriond has welcomed more than 10,000 scientists of all ages and statures from across the world.

The Rencontres was thus restructured around three major centres of interest: biology, high-energy physics and astrophysics. But the rest of science was not neglected. As the 1980s gave way to the 1990s, new subjects, sometimes only marginally related to the regular topics, would start to make an appearance. Among these topics were gravitational physics, mesoscopic physics, the search for the fifth force and for new laws in physics, and tests of the limits of existing laws.

As with all successful enterprises, Moriond has evolved. There are now more subjects, more meetings, more participants and more administration! But the spirit and excitement of those early days remain unabated. No discipline is an island unto itself, and the programme of each meeting, whatever its nominal subject, emphasizes the essential unity of the scientific endeavour.

During its 40 year lifetime, the Rencontres de Moriond has welcomed more than 10,000 scientists of all ages and statures from across the world. The meetings represent an important date in the scientist’s calendar. Since 1993 they have been sponsored by the European Union under the euroconference system, and thanks to this financial help, many young researchers have been able to participate – helping to maintain the youth and vigour of the meetings.

Spin-off events

The Rencontres de Moriond has stimulated the creation of other meetings organized in the same spirit: the Aspen Winter Conferences (US) and the Rencontres de Physique de la Valée d’Aoste (La Thuile, Italy) are flourishing examples, where frontier science is conducted in a warm and convivial atmosphere. The Rencontres de Blois, in existence for 17 years, represents another development of the Moriond spirit; these meetings are explicitly multidisciplinary in character, the subject changing from year to year, and culture replaces skiing during the break time.

Most recently, the Rencontres du Vietnam, which started in 1993, has taken this idea even further, with the explicit aim of helping Vietnam, still a developing country, realize its great potential. These meetings offer a forum in which scientists from Asia and the West can meet, present their work and forge new collaborations.

Which brings us to the present day, and to this year’s Rencontres de Moriond. In March it welcomed 20 times as many participants as the first meeting, incorporated audiovisual techniques that were unheard of 40 years ago, and enjoyed instantaneous contact with the world through the Internet. On the programme was research into fundamental questions that had not even been asked in 1966. The impressive set of proceedings, covering several decades, emphasized that we are in the golden age of physics, and that science is more vigorous than ever.

But the unique spirit of those early meetings lives on. Of the 400 participants at the 2005 meeting, 57% were younger than 35; of the 350 papers presented, 80% were read by young researchers; 60% of the participants were experimenters or observers and 40% were theorists. Sandwiched between three hours of morning talks and another three hours of hard work in the late afternoon was that traditional break, in which science, snow and sky combine to create new and ever-changing patterns.

What has the Moriond spirit brought to the scientific community? Nobel laureate James Cronin had this to say at the 20th anniversary of the Rencontres: “The Rencontres de Moriond has had a profound effect on the way we communicate in particle physics. It is a format which is extensively copied. The first Rencontres I attended was in 1971. There I learned for the first time about the GIM mechanism from Glashow and Iliopoulos. By having informal conversation on the ski slopes and in the bar at night, one could really understand why charm is necessary… I shall remember… the opportunity to discern the genuine humanity of our colleagues from all over the world.”

Learning About Particles – 50 Privileged Years

by Jack Steinberger, Springer. Hardback ISBN 3540213295, €39.95 (£30.50, $49.95).

Learning About Particles is an interesting excursion for the reader through the past 50 years of particle physics – 50 privileged years, as one is aptly reminded by the subtitle. Our guide is Jack Steinberger, undoubtedly one of the protagonists of those years, who offers a personal account of the historical and scientific evolution of the field, interspersed with autobiographical notes. He also makes sociological comments and expresses political views, but always gracefully, even when it is obvious that they must bring to memory particularly sad events.

CCEboo1_07-05 — Learning About Particles – 50 Privileged Years by Jack Steinberger

The book follows a chronological order, which at times is slightly violated in favour of more logical organization by topic to improve readability. It unfolds at two paces: pleasantly accurate with generous detail of experiments from the early years, and slightly rushed by the time experiments at the Large Electron Positron (LEP) collider are reached.

Particularly enjoyable are the first four chapters, which recount his years as graduate student, post-doc and young faculty in various prestigious institutions. Descriptions of early experiments and of the theoretical interests of the time are wisely mixed with personal recollections and anecdotes about the “gurus” of physics, and about the author’s young colleagues who later became very famous. The history is a little more difficult to follow into the next chapter, however, when dealing with strange particles.

Two chapters are dedicated to neutrinos, marking two moments of their “interaction” with Steinberger. After the first, the reader feels disappointed – more details of the conception of the fundamental “two-neutrino experiment” would have been expected, as would some “inside stories”. Perhaps the disappointment stems from anticipation created earlier in the book when a future collaboration between the then Captain Lederman and the then Private Steinberger is mentioned. As for inside stories, Steinberger confesses that initially he did not believe in neutral currents and this (quite rightly!) cost him a few bottles of good wine.

In the second of the two neutrino chapters, the steps towards the present understanding of the nucleon structure are retraced clearly – although with some haste – and the author brings the reader to present times with neutrino masses and oscillations. The intervening chapter on CP violation is an authoritative account of the achievements in the field since its beginning in 1957. Here Steinberger enumerates the spectacular accomplishments of the Standard Model within the context of the LEP experiments, perhaps with a tinge of nostalgia for earlier times.

It is difficult to identify precisely the intended audience for this book. It seems to be aimed at a variety of readers, not all necessarily from a scientific background, as the explanations given from time to time in the footnotes imply. This is, however, not done consistently and the result is often unsatisfactory. Furthermore, the occurrence of a few misprints at unfortunate places might prove disconcerting for the untrained reader.

Regardless of the audience, however, the book touches clearly upon the building blocks of the Standard Model and communicates 50 years of passion for physics and its intricacies – a lesson for young researchers. It also speaks of a passion for other, and far more common, sources of enjoyment in life such as music and mountains – a lesson for physicists in general!

EU decides on the future of research

On 20 April Europe’s seven major intergovernmental research organizations, working together in the EIROforum partnership, presented their comprehensive paper on science policy, “Towards a Europe of Knowledge and Innovation”.

Five years ago, at the meeting of the European Council in Lisbon, the creation of a European Research Area (ERA) was proposed as a means to achieve the ambitious targets necessary to develop a leading, knowledge-based economy in Europe.

Two years later the EIROforum partnership was created between seven of Europe’s major intergovernmental research organizations, the oldest of which is CERN. These organizations operate some of the largest research infrastructures in the world, with a combined budget comparable to that of the current Sixth Framework Programme (FP6) of the European Union (EU).

The EIROforum paper describes the partnership’s collective vision for the future of European scientific research necessary to support the Lisbon Process by working for the implementation of the ERA. The partners support the creation of a climate in Europe in which competitive research is undertaken in an efficient, cost-effective and successful manner. The aim is to be able to recruit and retain world-leading scientists in Europe, and at the same time help European industry by promoting joint front-line research that can generate important spin-offs. The paper presents many concrete ways in which the EIROforum organizations can participate effectively in the consolidation of the ERA.

A couple of weeks earlier, the European Commission adopted the proposal for the seventh Framework Programme (FP7). FPs are the EU’s main instrument for funding research in Europe. They cover a period of five years with the last year of one FP and the first year of the following FP overlapping. FP6 has been operational since 2003 with a total budget of €17.5 billion. FP7 will cover the period 2007-2013 with a budget of €72.7 billion and a time span of seven instead of five years. The ambitious proposal calls for improved efficiencies and aims to build on the achievements of previous programmes.

A new element is the establishment of a “European Research Council”, an independent, science-driven body that will fund European frontier research projects and ensure that European research is competitive at a global level. It will implement the peer review and selection process and will ensure the financial and scientific management of the grants. The EIROforum paper also supports this proposal.

In a third European initiative, on 8 April the European Strategy Forum on Research Infrastructures (ESFRI) presented the EU Commission with its paper “Towards New Research Infrastructures for Europe – the ESFRI ‘List of Opportunities'”. The forum was launched in April 2002 to support a coherent approach to policy-making on research infrastructures in Europe. Its horizon is the next 10-20 years.

The projects chosen had to be of pan-European interest, in an advanced state of maturity so that they can receive funds in FP7 and of international relevance. The forum wanted a “balanced” list that best corresponds to major needs of Europe’s scientific community. Out of a total of 23 opportunities, there were four projects on physics and astronomy, four on multidisciplinary facilities and one in computing.

Of the physics and astronomy projects, two are in nuclear physics, one in astronomy and one in neutrino physics (KM3NeT, a future deep underwater experiment in the Mediterranean). Multidisciplinary facilities include a European X-ray free-electron laser (XFEL) facility. The report also mentions, without specific details, five global projects with strong European participation, including the International Space Station (ISS) and the International Linear Collider (ILC).

• The seven EIRO forum members are the European Organization for Nuclear Research (CERN), the European Fusion Development Agreement (EFDA), the European Molecular Biology Laboratory (EMBL), the European Space Agency (ESA), the European Southern Observatory (ESO), the European Synchrotron Radiation Facility (ESRF) and the Institut Laue-Langevin (ILL).

Join the open-access revolution

There is a quiet revolution under way in academic publishing that will change how we publish and access scientific knowledge. “Open access”, made possible by new electronic tools, will give enormous benefits to all readers by providing free access to research results.

CCEvie1_06-05 — Ken Peach, director of particle physics, CCLRC Rutherford Appleton Laboratory.

The scientific articles published in journals under the traditional publishing paradigm are paid for through subscriptions by libraries and individuals, creating barriers for those unable to pay. The ever-increasing cost of the traditional publishing methods means that many libraries in Europe and the US – even the CERN Library, which is supposed to serve international researchers at a centre of excellence – are unable to offer complete coverage of their core subjects.

In 2003 the Berlin Declaration on open access to knowledge in the sciences and the humanities was launched at a meeting organized by the Max Planck Society. Six months later, the first practical actions towards implementing the recommendations of the declaration on an international level were formulated at a meeting held at CERN in May 2004. So far the declaration has been signed by 61 organizations throughout the world, which are now taking concrete measures for its implementation.

An obvious prerequisite for open access is that institutions implement a policy requiring their researchers to deposit a copy of all their published works in an open-access repository. The Council for the Central Laboratory of the Research Councils’ library committee in the UK sponsored such a project, ePubs, with the aim of achieving an archive of the scientific output of CCLRC in the form of journal articles, conference papers, technical reports, e-prints, theses and books, containing the full text where possible.

The feasibility study, carried out from January to March 2003, demonstrated the business need for this service within the organization. The data, going back to the mid-1960s, can be retrieved using the search interface or the many browse indices, which include year, author and journal title. In addition the ePubs system is today indexed by Google and Google Scholar. The scientific content of the system has further led Thomson ISI (the provider of information resources including Web of Knowledge and Science Citation Index) to classify ePubs as a high-quality resource.

The next step is to encourage the researchers – while of course fully respecting their academic freedom – to publish their research articles in open-access journals where a suitable journal exists.
In recent years new journals applying alternative publishing models have appeared in the arena. The problem so far is that none of these journals have a long-term business model. They are sponsored either by a research organization or by other titles in the publisher’s portfolio, or enjoy sponsorship that will not last forever.

Scientific publishing has a price and will continue to have a price, currently mainly covered by academic libraries through subscriptions. Moving to an open-access publishing model should dramatically reduce the global cost for the whole of the academic community. The publication costs should be considered a part of the research cost and the research administrators should budget for these when the research budgets are allocated. However, a change must not take place without safeguarding the peer-review system, which is the guarantor of scientific quality and integrity.

Outside biology and medicine, few journals that support open access are given the same academic credits as the traditional journals. This situation is further reinforced if there is a direct coupling between research funding and the “impact factors” of journals where results are published. However, by taking the risk and publishing important work in new journals that implement the open-access paradigm, the impact factor will automatically be enhanced.

The example of the Journal of High Energy Physics (JHEP) is striking. This relatively new journal was launched by the International School for Advanced Studies (SISSA) in Trieste in 1997. Today some studies give it an impact factor close to that of Physical Review Letters in publishing papers on high-energy physics. JHEP was launched ahead of its time and was forced, because of the lack of financial support, to become a subscription journal. However, with the support of the main physics laboratories, it would be possible in the present climate for this successful journal to enter the open-access arena once again.

If a change is wanted, it is up to us. Particle physics cannot change the world alone, but a clear position among our authors and our members of editorial boards will have a strong synergy with our colleagues pulling in the same direction in other fields.

Large Hadron Collider Phenomenology

by M Krämer and F J P Soler (eds), Institute of Physics Publishing. Hardback ISBN 0750309865, £75 ($125).

The Large Hadron Collider (LHC) is often described as the machine needed by the worldwide community of high-energy particle physics experimentalists and theorists to search for and, it is hoped, discover physics signals beyond those expected from the Standard Model of particle interactions. The general-purpose experiments now completing construction (ATLAS and CMS) are often described as huge facilities optimized for the search for the elusive Higgs boson, the one key element missing in the Standard Model. About three years from now, the whole community in our field will focus on new and, we hope, unexpected physics results. These will cover a wide range of topics, extending over all possible theoretical conjectures published to date, that are relevant to experiments at the scale of tera-electron-volts.

CCEboo1_05-05 — Large Hadron Collider Phenomenology by M Krämer and F J P Soler

Given the dearth of guidance from experiments (aside from the beautiful but maddening agreement of even the most precise measurements with the predictions of the Standard Model), the driving goal of all theoretical developments beyond this very same Standard Model is that of solving the many fundamental issues in particle physics, which today are also relevant to cosmology, a science that has become much more mature experimentally over the past 10 years or so.

This book presents a series of lectures attempting to cover LHC phenomenology in the broadest possible sense. They range on one side from the intricacies of scalar fields, string theory and extra dimensions, to the basics of detector physics, which for more than 10 years has guided R&D in our field. This has led to the optimized design of the huge and complex detectors needed to extract minute signals from the huge backgrounds, involving today’s exciting physics (electroweak gauge-boson production, quantum chromodynamic multi-jet events, and heavy flavour production). But the lectures also range from accelerator science to modern e-science (the birth of the computing Grid) and from the less well known intricacies of heavy-ion physics to those of forward physics, where diffractive and quasi-elastic phenomena dominate.

These lectures were meant for today’s young physicists, many of whom will surely be the driving force behind the physics analyses and publications of the LHC experiments over the coming years. They were delivered on the occasion of the 57th Scottish Universities Summer School in Physics in summer 2003, by a well balanced mix of experienced theorists (D Ross, K Ellis and J Ellis) and seasoned experimentalists (V Gibson, H Hoffmann, B Müller, M A Parker, A de Roeck, R Schmidt and T S Virdee).

The emphasis in most of the lectures was on giving a snapshot of the current status of understanding in theory, phenomenology and accelerator and detector performance. The inevitable fate of such snapshots is to become fairly quickly obsolete, given the huge ongoing development of both the hardware and the software (should one add the middleware?) needed to operate the experiments, to simulate their performance accurately, to analyse their data quickly but unerringly, and to give a fair chance to all participants on all continents to join in the fun in the summer of 2007. Another drawback of such attempts is that, unavoidably, certain topics are treated superficially. However, I believe upon reading large sections of the book that this is largely outweighed by the benefit, for the young and less young reader, of finding in one volume a really complete coverage of all aspects relevant to LHC physics with a sufficiently rich bibliography to pursue in-depth reading.

For example, the reader interested in the phenomenology of quantum chromodynamic (QCD) beyond its direct application to LHC physics is referred to the book QCD and Collider Physics (by K Ellis, J Stirling and B Webber, 1996), the reader interested in more in-depth studies of accelerator physics and technology is referred to the Handbook of Accelerator Physics and Engineering (by A Chao and M Tigner, 2002), and the reader interested in the design and optimization of the general-purpose ATLAS and CMS detectors is referred to “Experimental challenges in high luminosity collider physics” (by N Ellis and T S Virdee, Ann. Rev. Nucl. Part. Sci. 44 609, 1994) and to all the Technical Design Reports published from these experiments between 1996 and 2005.

In summary, this book is an excellent introduction to LHC physics for any person entering the field now, at a moment when a huge effort from the whole community is still ongoing to meet the difficult challenge of assembling the various jigsaws needed to observe the first proton-proton collisions at the tera-electron-volt scale in summer 2007.

The reader has to be aware though that, apart from the foundations of the Standard Model, of supersymmetric and string theories, and of particle interactions in matter, many of the details provided in the lectures to illustrate the wonderful and exciting potential of the LHC and its associated detectors are to be considered as examples only. These will most likely bear little resemblance to the results published in the final publications a few (or many) years from now. I believe that most experimentalists, who have devoted a large fraction of their professional lives to make the LHC dream come true, hope that reality at the tera-electron-volt scale is something quite different from what has been envisaged to date by our theory colleagues. It is indeed the fulfilment of such a hope that can give a new and much needed impetus to our field, thereby surely opening up rich and thrilling prospects for the generations of theorists and experimentalists to come.

US budget changes priorities for HEP

On 8 February the White House released its budget proposal for the financial year 2006. The science and technology budget of the US Department of Energy has been reduced overall by about 3.8% compared with 2005, whereas the budget for high-energy physics (HEP) is reduced by about 3%. The proposal is pending approval by Congress.

The HEP programme for 2006 has been structured in such a way “not only to maximize the scientific returns on our investment in these facilities, but also to invest in R&D now for the most promising new facilities that will come online in the next decade”. This has necessitated some prioritization.

The planned operations, upgrade and infrastructure for the Tevatron at Fermilab are cited as the highest priority, with a high priority also given to operations, upgrades and infrastructure of the B-factory at SLAC. However, B-factory operations will be terminated by 2008 at the latest. Support for a leadership role for US research groups in the physics programme for the Large Hadron Collider at CERN will also continue to be a high priority, and the preconceptual R&D needed to explore the nature of dark energy will continue in 2006.

A major casualty is the engineering design of the B Physics at the Tevatron (BTeV) experiment, which was scheduled to begin in 2005 as a new “major item of equipment” and will instead be terminated by the end of 2005. The reasons given are the timescale and the “lesser scientific potential” compared with other projects, although it is “still important scientifically”. Support was strong only if the project could be completed by 2010, which is “not feasible given schedule and funding constraints”.

Support for a future electron-positron linear collider, however, has increased relative to 2005 for “the continued international participation and leadership in linear collider R&D and planning by US scientists”. R&D for other new accelerator and detector technologies, particularly in the emerging area of neutrino physics, will also increase.

Cornell gets funding for brighter X-rays

The US National Science Foundation (NSF) has awarded Cornell University $18 million to begin developing a high-brilliance, high-current Energy Recovery Linac (ERL) synchrotron radiation X-ray source.

CCEnew7_04-05 — In the proposed Energy Recovery Linac, electrons are accelerated to high energy, and produce X-rays in one trip around a ring of magnets. Returning electrons give up their remaining energy to the microwaves in the linac before they are dumped.

All existing hard X-ray synchrotron radiation facilities are based on storage rings. Equilibrium emittance considerations limit the X-ray brilliance that is practically attainable and the ability to make short intense X-ray pulses. In an ERL the electron bunches are not stored; rather, electron bunches with very low emittance are created then accelerated by a superconducting linac.

After one circuit around a transport loop, where the X-rays are produced, the electron energy is extracted back into the radio-frequency (RF) field of the linac and used to accelerate new bunches. The energy-depleted bunches are dumped.

The beams from ERLs are predicted to be around 1000 times better in terms of brightness, coherence and pulse duration than current X-rays. They will enable investigations that are impossible to perform with existing X-ray sources.

The ERL is based on accelerator physics and superconducting microwave technology in which Cornell’s Laboratory of Elementary Particle Physics is a world leader. The NSF award to Cornell will fund the prototyping of critical components of the machine. The design team, led by Cornell’s professors Sol Gruner and Maury Tigner, has already almost completed the prototype design; scientists from Jefferson Laboratory worked with Cornell on the initial design. Prototype construction and testing should finish in 2008. Cornell then will seek funding for a full-scale ERL facility as an upgrade of the present synchrotron radiation facility, the Cornell High Energy Synchrotron Source (CHESS), which is based on the Cornell Electron Storage Ring (CESR).

Very High Energy Cosmic Gamma Radiation: A Crucial Window on the Extreme Universe

by Felix A Aharonian, World Scientific. Hardback ISBN 9810245734, £65 ($107).

Astronomy – the study of all kinds of cosmic radiation – meets particle physics at the highest gamma-ray energies. This book offers the opportunity for particle physicists to cross the bridge between the two disciplines. They will discover the nature and properties of the extreme sources in the universe able to emit photons at energies higher than 10 GeV.

CCEboo1_04-05 — Supernova remnants, such as the Crab Nebula, figure among the many high-energy gamma-ray sources described by Aharonian. Image: European Southern Observatory.

Very-high-energy astrophysics is entering a new era with the recent achievement by the High Energy Stereoscopic System (HESS) of the first spatially resolved high-energy gamma-ray image of an astronomical object, the supernova remnant RX J1713.7-3946. This image confirms that supernova remnants are at the origin of cosmic rays.

The lead author of the paper in Nature that described the HESS results was Felix Aharonian, the author of this book. Here he uses his expertise to provide a broad and comprehensive overview of the study of cosmic gamma rays, from energies of about 10 GeV to 10 TeV. In nearly 500 pages, he covers all aspects of the field including the theoretical ground of gamma-ray emission and absorption mechanisms, as well as the status of detection facilities. The main part of the book is, however, devoted to the phenomenology of the various sources of very-high-energy gamma rays.

With more figures than equations, the author guides us through the world of supernova remnants, pulsars, jets of quasars and microquasars, and clusters of galaxies. He even discusses the implications for cosmology, as derived from the interaction of very-high-energy gamma rays with the diffuse extragalactic background radiation. As complete as this book tends to be, however, I am a little surprised to find notable omissions, including gamma-ray bursts and the possible annihilation-radiation of weakly interacting massive particules (WIMPs), which are mentioned but not discussed.

Nevertheless, this book with its extensive list of references is a very valuable introduction to the astrophysics of high-energy gamma-ray radiation. Well structured and with its more mathematical parts left for the appendix, it is also suitable for a quick search for a specific topic. It can therefore be used as a reference book for this fascinating “last electromagnetic window” on the cosmos, a topic destined to evolve very rapidly in the coming years.

Debunked! ESP, Telekinesis and Other Pseudoscience

by Georges Charpak and Henri Broch, translated by Bart K Holland, Johns Hopkins University Press. Hardback ISBN 0801878675, $25.

CCEboo1_03-05 — Debunked! ESP, Telekinesis and Other Pseudoscience by Georges Charpak and Henri Broch

Georges Charpak will, as they say, need no introduction to most readers of the CERN Courier. Henri Broch, author of Au Coeur de l’Extraordinaire and a contributor to the American magazine Skeptical Inquirer, is perhaps less familiar to English-speaking readers. Now, their short book Devenez Sorciers, Devenez Savants has been translated into English by Bart Holland, with the title Debunked! ESP, Telekinesis and Other Pseudoscience.

Pseudoscientific mumbo-jumbo has been engulfing the US long enough for an extensive sceptical literature to have grown up around it. Stories about firewalking, dowsing and spoon-benders have already been dealt with by James Randi in Flim-Flam!, Martin Gardner in Science: Good, Bad and Bogus, and, less originally in my opinion, by Victor Stenger in Physics and Psychics. Charpak and Broch treat all these matters with new insight and humour, but include many new examples to show that even France, home of the Cartesian philosophy of doubt and scepticism, is now apparently ready to believe almost anything, provided it is vouched for by fashionable figures in show business or the media.

Thus, in 1982, Broch found that among undergraduate science students at Nice, 52% believed relativistic time dilatation to be pure theoretical speculation, while 68% thought that paranormal spoon-bending was scientifically proven. More recently, Elizabeth Teissier, astrological adviser to millions (including, she would have us believe, François Mitterrand), was awarded a PhD by the Sorbonne for a thinly disguised PR job vaunting her craft.

I cannot resist mentioning two of my own favourites here: Paco Rabanne, the famous fashion designer, ran away from Paris before the 1999 eclipse because he was afraid the sky might fall on his head; and the failed rock musician and racing-car writer Claude Vorilhon, a.k.a. Rael, recently got word about particle physics from the Elohim – the “extraterrestrial guardians”, he says, “of peace, non-violence and harmony at all levels of infinity”. Vorilhon e-mailed many physicists to pass on the message not to mess with the universe by constructing super-colliders; science is good and should be unlimited as long as it fuses elements, it would seem, but it should never be used when breaking or cracking infinitely small particles. As Charpak and Broch point out, the more vague, hollow and absurd the claim, the deeper the truth drawn from it – a phenomenon they term the “Well Effect”.

In his introduction, Bart Holland explains that he has tried to be true to the French original. The result will sometimes be quite confusing to English-speaking readers unfamiliar with what he calls the “glorious Gallic rhetorical style”. In addition, he has not always followed his own rule of keeping sections dealing with popular French culture and public figures intact, but has supplemented them with explanatory footnotes. In several cases, I had to turn to the original version to put arguments into context.

In their final chapter, Charpak and Broch strongly criticize the media, which they see as the natural ally of science and reason, for often (unwittingly or not) promoting the bogus claim that all ideas are of equal value, under the guise of journalistic even-handedness. The authors also differ from their English-language counterparts in that they see wider dangers in pseudoscience, such as its threat to democracy and the emergence of a multinational big business to market it. The authors’ parting advice to the reader is that critical faculties should be allied with human ones. This was more or less the position taken by Sir Walter Raleigh, who once wrote, “The skeptick doth neither affirm nor deny any position but doubteth of it, and applyeth his Reason against that which is affirmed, or denied, to justify his non-consenting.” He was beheaded shortly afterwards.

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