By Chiang Tsai-Chien (translated by Wong Tang-Fong) World Scientific
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The discovery of parity non-conservation was honoured with a Nobel Prize in Physics awarded to Chen-Ning Yang and Tsung-Dao Lee who raised the “question of parity conservation in weak interactions” in 1956 (Phys. Rev.104 254). Originally the preprint contained a question mark – “Is parity conserved in weak interactions?” – but the editors of Physical Review at that time discouraged question marks in the titles of regular articles. The crucial question mark was eliminated forever the same year by the valiant effort of Chien-Shiung Wu and her collaborators – Ernest Ambler, Raymond Hayward, Dale Hoppes and Ralph Hudson. They conducted a memorable experiment at the National Bureau of Standards and the results were published in the first few months of 1957 (Phys. Rev.105 1413). The concept of their experiment was remarkably simple: take a β-decay source (cobalt-60) and magnetize it with a circular current flowing first in one direction and then in the opposite sense, so that the initial states are the mirror images of each other. The β decays of the mirror-symmetric initial states turned out to be non-mirror-symmetric. Immediately afterwards, two other groups published similar evidence for parity non-conservation – Richard Garwin, Leon Lederman and Marcel Weinrich in Columbia University and Jerome Friedman and Valentine Telegdi in Chicago.
Weak interactions are at the heart of this interesting biography. Of course, Wu was not the first lady working in physics – other remarkable women preceded her in the path to great discoveries. However, as the author argues, she was a person of many “firsts”, such as the first recipient of the Wolf prize and the first female president of the American Physical Society.
The biography tells the exciting story of a young woman who left the rural China vividly described in the novels of Pearl S Buck and became one of the recognized authorities in the physics of β decay. Wu joined the Manhattan Project and later worked on several other topics, ranging from the Mossbauer effect to exotic atoms. However, her main contributions remain connected to weak interactions. In collaboration with her group in Columbia she also tested the conserved vector-current hypothesis and the universality of Fermi interaction proposed by Richard Feynman and Murray Gell-Mann – a discovery that was essential for the subsequent development of the Standard Model of electroweak interactions.
Wu was above all a scientist who did not like much exposure and dramatic headlines. She also had a wonderful family and various interests, including the rights of women in science. After leaving Shanghai in 1936, she was not allowed back into mainland China for 37 years and so never again saw family members who had died in the meantime. The Cultural Revolution threatened Chinese science but did not succeed. A number of remarkable Chinese scientists, including Wu, contributed enormously to the current success of the standard electroweak theory.
On 29 August 2013, on the ground floor of Building FST01 of the Faculty of Pure and Applied Sciences at the University of Cyprus in Nicosia, 31 students filed silently into the two classrooms of the CERN School of Computing and took a seat in front of a computer. An hour later they were followed by a second wave of 31 students. They were all there to participate in the 12th occasion of a unique CERN initiative – the final examination of its computing school.
The CERN School of Computing (CSC) is one of the three schools that CERN has set up to deliver knowledge in the organization’s main scientific and technical pillars – physics, accelerators and computing. Like its counterparts, the CERN Accelerator School and what is now the European School of High-Energy Physics, each year it attracts several-dozen participants from across the world for a fortnight of activities relating to its main topic.
How and why was the CSC set up? On 23 September 1968, future director-general Léon van Hove put forward a proposal to the then director-general, Bernard Gregory, for the creation of a summer school on data handling. This followed a recommendation made on 21 May 1968 to the Academic Training Committee by Ross MacLeod, head of the Data and Documents Division, the forerunner of today’s Information Technology Department. The proposal recommended that a school be organized in summer 1969 or 1970. The memorandum from van Hove to Gregory gave a visionary description of the potential audience for this new school: “It would address a mixed audience of young high-energy physicists and computer scientists.” Forty-five years later, not a word needs to be changed.
The justification for the school was also prophetic: “One of the interests of the Data Handling Summer School lies in the fact that it would be useful not only for high-energy physicists but also for those working in applied mathematics and computing. It would be an excellent opportunity for CERN to strengthen its contacts with a field which may well play a growing role in the long-range future.” With the agreement of Mervyn Hine, director of research, Gregory approved the proposal on 15 November 1968 and on 20 December MacLeod proposed a list of names to van Hove to form the first organizing committee. Alongside people from outside CERN – Bernard Levrat, John Burren and Peter Kirstein – were Tor Bloch, Rudi Böck, Bernard French, Robert Hagedorn, Lew Kowarski, Carlo Rubbia and Paolo Zanella from CERN.
The first CSC was not held at CERN as initially proposed but in Varenna, Italy, in 1970. It was realized quickly that the computing school – with the physics and accelerator schools – could be effective for collaboration between national physics communities and CERN. Until 1986 the CSC was organized every other year, then yearly starting with the school in Troia, Portugal, in 1987. To date there have been 36 schools, attended by 2300 students from five continents.
Ten years ago, I took over the reins of the school and proposed a redefinition of its objectives as it entered its fourth decade: “The school’s main aim is to create and share a common culture in the field of scientific computing, which is a strategic necessity to promote mobility within CERN and between institutes, and to carry out large transnational computing projects. The second aim is the creation of strong social links between participants, students and teachers alike, to reinforce the cohesion of the community and improve the effectiveness of its shared initiatives. The school should be open to computer scientists and physicists and ensure that both groups get to know each other and acquire a solid grounding in whichever of these domains is not their own.”
Moreover, the new management proposed three major changes of direction. First, they vowed to reinvigorate the resolutely academic dimension of the CSC, which during the years had gradually and imperceptibly become more like a conference. Conferences are necessary for scientific progress – they are forums where people can present their work, have their ideas challenged, have fruitful discussions about controversial issues and talk about themselves and what they do. The interventions at conferences are short, sometimes redundant or contradictory. The transmission of facts and opinions becomes more prominent than the transfer of knowledge. I took the view that this should not be the primary role of the CSC, since conferences such as the Computing in High-Energy Physics series serve this purpose perfectly. The academic dimension was therefore progressively re-established through the implementation of three principles.
Three principles
The first academic principle concerns the organization of the teaching. A deliberately limited number of teachers – each giving a series of lessons of several hours – ensures coherence between the different classes, avoids redundancy and delivers consistent content, more than a series of short interventions. Moreover, for several years now all of the non-CERN teachers have been university professors. This is not the result of a strict policy but it is worthy of note that the choice of teachers has been consistent with this academic ambition.
The second principle for restoring the academic dimension concerns the school’s curriculum. The main accent is on the transmission of knowledge and not of know-how. In this way, the CSC differs from training programmes organized by the laboratories and institutes, which are focused on know-how. The difference between knowledge and know-how is an important principle in the field of learning sciences. To get a better understanding of this distinction, the management of the school established relations with experts in the field at an early stage, particularly at the University of Geneva.
Knowledge is made up of fundamental concepts and facts on which additional knowledge is built and developed to persist over time
What are the differences? Knowledge is made up of fundamental concepts and facts on which additional knowledge is built and developed to persist over time. Moreover, the student acquires knowledge, incorporates it into his or her personal knowledge corpus and transforms it. Two physicists never have the same understanding of quantum mechanics. On the other hand, know-how – which includes methods and the use of tools – can generally be acquired autonomously with few prerequisites. With the exception of physical skills – such as knowing how to ride a bike or swim – which we tend not to lose, know-how requires regular practise so that it is not forgotten. Knowledge is more enduring by nature. Finally – and this is one of the main differences – knowledge can be transposed more readily to other environments and adapted to new problems. That at least is the theory. In practice, the differences are sometimes less clear. This is the challenge with which the CSC tries to get to grips each year when defining its programme – are we really operating mainly in the field of knowledge? The school is made up in equal parts of lectures and hands-on sessions, so do the latter not relate more to know-how? Yes, but the acquisition of this know-how is not an end in itself – it provides knowledge with a better anchorage.
The third principle of the academic dimension is evaluation of the knowledge acquired and recognition of the required level of excellence with a certificate. Following requests from students who wanted the high level of knowledge gained during the school to be formally certified, the CSC Diploma was introduced in 2002 to recognize success in the final exam and vouch for the student’s diligence throughout the programme. To date, 671 students have been awarded the CSC Diploma, which often figures prominently in their CVs. But that’s not all. Since 2008, the academic quality of the school, its teachers and exam has been formally audited each year by a different independent university. Each autumn, the school management prepares a file that is aimed at integrating the next school into the academic curriculum of the host university. The universities of Brunel, Copenhagen, Gjøvik, Göttingen, Nicosia and Uppsala have analysed and accepted CERN’s request. As a result, they have each awarded a formal European Credit Transfer System (ECTS) certificate to complement the CERN diploma.
This academic reorientation of the school is one of the three main renewal projects undertaken during the past 10 years. The second relates to the school’s social dimension. The creation of social links and networks between the participants and with their teachers has become the school’s second aim. This is considered to be a strategic objective because not only does it reinforce the cohesion of the community, it also improves the efficiency of large projects or services, such as the Worldwide LHC Computing Grid, through improved mutual understanding between the individuals contributing to them.
The main vehicle chosen for socialization is sport. Every afternoon, a large part of the timetable is freed up for a dozen indoor and outdoor sports. Tennis, climbing or swimming lessons are given, often by the school’s teachers. Each year, participants discover an activity that is new to them, such as horse riding, sailing, canoeing, kayaking, scuba diving, rock climbing, cricket and mountain biking. The sport programme is supported by the CERN Medical Service and is associated with the “Move! Eat better” initiative. A second vehicle for socialization – music – is being considered and could be introduced for future schools. The intention is to give those who are interested the opportunity each afternoon to take part in instrumental music or choral singing or to discover them for the first time, with the same aim as for sport of “doing things together to get to know each other better”.
The third renewal project is plurality. In contrast to CERN’s high-energy physics and accelerator schools, which have organized several annual events for a number of years, the CSC has long remained the organization’s only school in the field of computing. However, since 2005 the CSC management has organized the inverted CSC (iCSC, “Where students turn into teachers”) and starting in 2013 the thematic CSC (tCSC). The idea behind the inverted school is simple – to capitalize on the considerable amount of knowledge accumulated by the participants in a school by inviting them to teach one or more lessons at a short school of three to five half-days, organized at CERN at the mid-point between two summer schools. To date, 40 former students have taught at one of these inverted schools.
It should be noted that the academic principle is still predominant. The goal is not to talk about oneself or one’s project but to present a topic, an innovative one if possible. This is not always easy, so each young teacher who is selected is assigned a mentor who follows the design and production of the lesson across three months. The inverted school has another aim – it is also a school for learning to teach. It represents the second link in a chain of training stages for new teachers for the main school. The first link, for those who are interested, is to give a short academic presentation while attending the main school. After the iCSC, i.e. the second link, some are invited to give an hour’s lesson at the main school before the last stage – their full integration into the teaching staff. This process generally takes several years.
During the latest CSC in Nicosia, five out of the 11 teachers were younger than 35. Three of them had passed through the CSC training chain. Along with their forthcoming colleagues, they are the future of the school. Leaving the CSC after 11 years as its director, I am confident that the next generation is ready to take up the baton.
Bruno Pontecorvo (1913–1993) was born in Pisa but his scientific life began in Rome, when he was accepted into the group of physicists working at Sapienza University of Roma with Enrico Fermi. It was a small but exceptional group of young people attracted by the strong personality of Fermi, who were later known as “the boys of Via Panisperna” from the name of the street where the physics institute was located at that time. Pontecorvo arrived in Rome in time to participate in the discovery of radioactivity induced by slow neutrons, for which Fermi was to receive the Nobel Prize in Physics in 1938. A famous picture shows the group at the time of the discovery, with the notable absence of Bruno (figure 1). This was for good reason – he was behind the camera, taking the picture.
On 11–12 September 2013, Sapienza University of Rome celebrated Pontecorvo’s centenary with an international scientific symposium – The Legacy of Bruno Pontecorvo: the Man and the Scientist. (Another was held later in Pisa.) Inaugurated in the presence of the president of the republic, Giorgio Napolitano (figure 2), it was attended by distinguished physicists from Italy and other European countries, as well as Japan, Russia, the US and CERN. The talks revisited different sides of Pontecorvo’s long and multifaceted scientific life, which was marked by his lucid and deep passion for science and his important contributions to several branches of nuclear and particle physics.
It was a life sharply divided in two parts by his sudden move to the Soviet Union in the summer of 1950, when he went from England via Italy and Sweden, to reappear five years later in Dubna as part of the Soviet scientific establishment. Presenting an historical perspective of Pontecorvo’s life, Frank Close spoke of “a life of two halves”. One could add a third life – the one lived during the decline and dissolution of the Soviet system, with periodic visits to Italy and disenchantment in the 1980s, which are well described in a book by Miriam Mafai, Il lungo freddo (The Long Cold), published in 1990.
Jack Steinberger opened the meeting by speaking about when he was a student of Fermi and Pontecorvo came to Chicago from Canada to visit his old mentor. Pontecorvo had discovered that the capture of the muon by nuclei, measured by Marcello Conversi, Ettore Pancini and Oreste Piccioni in Rome, was consistent with having the same strength as electron capture – that is, that the muon and the electron, besides having the same electric charge, share the same coupling in the weak interaction. It was the start of the lepton family and the universality of the weak interaction, which would eventually evolve into the long story of electroweak unification. Steinberger was doing his thesis with Fermi on muon decay, which led him to discover the continuum character of the electron’s spectrum, entirely analogous to nuclear beta decay.
Pontecorvo’s research during his Canadian period was presented by Giuseppe Fidecaro, who delved into the development of the radiochemical method to detect neutrinos – later applied by Raymond Davis to detect solar neutrinos. Luigi Di Lella described the studies by Pontecorvo and Ted Hincks on muon decay, including the search for the decay μ → e γ – a long saga, which also saw Steinberger as a protagonist and which continues today with the MEG experiment at PSI. Di Lella ended with the ideas that Pontecorvo developed in Dubna on high-energy neutrino interactions, somehow anticipating the independent line of research carried out at Brookhaven by Leon Lederman, Melvin Schwarz and Steinberger, which eventually led to the discovery of the two kinds of neutrino in 1962 and the award of the Nobel prize in 1988.
An important part of the conference was dedicated to neutrino oscillations – Pontecorvo’s other great intuition – with an update on solar and atmospheric neutrino oscillations by Till Kirsten and Yoichiro Suzuki, respectively. An overall view was given by Samoil Bilenky from Dubna, who was a collaborator and friend of Pontecorvo for a long time.
In Dubna, Pontecorvo became the reference figure for many Russian physicists and also for the physicists from Western Europe and CERN who visited countries in the East (figure 3). Ettore Fiorini brought his recollections of Pontecorvo at the Balaton School, in Hungary, at the time of the discovery of neutral currents, while Ugo Amaldi spoke of his relations with Pontecorvo at Dubna, when the Russian participation in the DELPHI experiment at the Large-Electron Positron collider was taking shape.
Two historical talks gave an idea of the depth of Bruno Pontecorvo’s personality.
Nadia Robotti documented the path of Pontecorvo in the Panisperna group. From his initial position as the youngest and most inexperienced member of the group – he was called “the cub” – he went on to become in few years a respected researcher, signing one publication with Fermi and Rasetti alone, and owner of part of the slow-neutron technologies. Later, when the group in Rome started to split up, Pontecorvo moved independently from Fermi to find a position in Paris, in the laboratory of Frédéric Joliot and Irène Curie, where he arrived in spring 1936 as a fully formed and independent investigator in the most advanced fields of nuclear physics.
Precious testimony
In a second historical talk, Rino Castaldi brought a precious testimony from when Pontecorvo arrived in Dubna. It was a hand-written log book begun on 1 November 1950, which Gloria Spandre and Elena Volterrani obtained from Pontecorvo’s eldest son, Gil. Page after page, written in minute but precise writing with remarkably few cancellations, reconstruct a picture of Pontecorvo building up his future activity in particle physics in the new laboratory where he had chosen to spend his life. From issues in the life of an experimental physicist and ideas about new experiments, through glimpses about his thoughts on the mysterious strongly produced but long-lived particles (the strange particles), to a tantalizing formula for muon beta decay, with one neutrino encircled and the other in a box (figure 4) – could this be a hint that the two neutrinos might be different? We can leave the answer to Pontecorvo himself. Much later, he described his earlier activity on the weak interaction in a contribution to the International Colloquium on Particle Physics in Paris in July 1982:
“I have to come back a long way (1947–1950). Several groups, among which J Steinberger, E Hincks and I, and others were investigating the (cosmic) muon decay. The result of the investigations was that the decaying muon emits 3 particles: one electron…and two neutral particles, which were called by various people in different ways: two neutrinos, neutrino and neutretto, ν and ν´, etc. I am saying this to make clear that for people working on muons in the old times, the question about different types of neutrinos has always been present…for people like Bernardini, Steinberger, Hincks and me…the two neutrino question was never forgotten.”
The centenary symposium took place in the Aula Magna of Sapienza University in Rome, where Fermi worked from 1935 to 1938, the year of his departure to Stockholm (for the Nobel prize) and then to the US. Organized with efficiency by the indefatigable Carlo Dionisi, professor of physics at Sapienza, it was an occasion for the larger Pontecorvo family – the Italian and Russian branches – to gather, cheer and greet friends and colleagues.
From 1945 to 1990, the development of scientific educational and research capacities in physics in the Balkans followed the political and economic courses of the relevant countries. Yugoslavia and the six republics in its federation developed ties – to a greater or lesser extent – with both the East and the West, while Romania and Bulgaria became well integrated into the scientific system of the Soviet Union and the Eastern Bloc. In these countries and in the entire Balkans, the period was marked by a significant increase in the number of scientists – primarily in the field of physics – and scientific publications. There was also a substantial rise in the level of university education and scientific infrastructure, which had been lower before the Second World War or limited to a small number of exceptional yet isolated individuals or smaller institutions. Greece and Turkey were connected mainly to the US or Western Europe, while Albania was in self-imposed isolation for much of this period.
The years following 1990 brought significant changes, which were particularly dramatic and negative for the countries that were created after the break-up of Yugoslavia. The wars waged on the territory of the former Socialist Federal Republic of Yugoslavia and enormous economic problems resulted in the devastation of scientific capacities, the leaving of mainly young physicists and the stopping of many programmes and once-traditional scientific meetings – in particular the world-renowned “Adriatic meetings”. Less dramatic but more significant changes took place in Bulgaria, Romania and even Moldavia and the Ukraine – countries on the periphery of the Balkans but in the same neighbourhood. The number and quality of students graduating in physics, as well as financial investment in all forms of scientific educational work, plummeted. The number of researchers and PhD students, in particular, dropped so significantly in the majority of university centres that the critical mass necessary for teaching at graduate level as well as for teamwork and competitiveness was lost. The remaining young research groups and students – some only 100 km apart – had no form of communication, exchange or co-operation. European integration – if it began at all – proceeded slowly, while many previously established ties were severed.
Wess and WIGV
The origins of the Southeastern European Network in Mathematical and Theoretical Physics (SEENET-MTP) are linked to Julius Wess and his initiative “Wissenschaftler in globaler Verantwortung” (WIGV) – “Scientists in global responsibility” – launched in 1999 (Möller 2012). Wess was professor at the Ludwig Maximilian University (LMU) of Munich and director of the Max Planck Institute (MPI) for Physics in Munich. Like most people in Europe, he deplored the Yugoslav Wars of the 1990s and this eventually turned into a resolve to engage hands-on in re-establishing scientific co-operation with the scientists of former Yugoslavia during the “Triangle meeting” in Zagreb in 1999. Wess collected information about the remaining links between scientists in the new countries of the former Yugoslavia and the rest of the world, and especially between the former Yugoslav countries. He also found out about the institutional and economic situation of the universities and institutes.
The first network meeting of WIGV was organized in Maribor, Slovenia, in May 2000
The first network meeting of WIGV was organized in Maribor, Slovenia, in May 2000. It was followed by activities such as the Eighth Adriatic Meeting in Dubrovnik, Croatia, and the First German-Serbian School in Modern Mathematical Physics in Soko Banja, Serbia, in 2001. Three postdoc positions and many short-term fellowships were established in Munich, supported by the German Academic Exchange Service (DAAD), the German Research Foundation (DFG) and the Federal Ministry of Education and Research (BMBF). The biggest and, in a sense, the most important action was the Scientific Information Network for South East Europe (SINSEE/SINYU) project to establish new high-speed fibre capacity across large distances, especially for the scientific community, with SINYU covering the region of the former Yugoslavia.
Unfortunately, between the summers of 2002 and 2003 the WIGV initiative lost its momentum. Many of the financial ad-hoc instruments created for the region ended during this time. Wess also needed to pause because of serious health problems in 2003. However, between October 2000 and December 2002 the idea of a “southeastern European” rather than “Yugoslav” network in mathematical and theoretical physics emerged and evolved in discussions between Wess, myself and other colleagues who visited Munich or took part in numerous meetings supported by WIGV.
Our impression was that a critical mass of students and researchers in the region of the former Yugoslavia could not be achieved and that a larger context should be attempted – the Balkans. In addition to the former Yugoslavia, this would include Bulgaria, Greece, Romania, Turkey, etc. We hoped that this kind of approach would have a political as well as scientific dimension, alongside other benefits. Agreement was quickly reached and the name Southeastern European Network in Mathematical and Theoretical Physics (SEENET-MTP) was created. With the personal recommendations of Wess, I visited CERN, the International Centre for Theoretical Physics (ICTP), the UNESCO headquarters in Paris and the UNESCO Venice office to promote the idea. In the course of discussions, the foundations were laid for support for the future network.
The SEENET-MTP Network
The founding meeting of the network was set up as a workshop – the Balkan Workshop (BW2003) on Mathematical, Theoretical and Phenomenological Challenges Beyond the Standard Model, with Perspectives of Balkans collaboration – that was held as a satellite meeting of the Fifth General Conference of the Balkan Physical Union, in Vrnjačka Banja, Serbia, in August 2003. This made it possible to have a regional meeting, with representatives from nearly all of the relevant countries present. Unlike the First German–Serbian School and some other actions, Germany’s contribution to the budget of BW2003 was no more than a third. The organization of the workshop was not without some controversy. It was a difficult but important lesson in the writing of applications for funding, proposals for projects and their implementation. The meeting, which had excellent lecturers, ended with the ratification of a letter of intent, followed by the election of myself as co-ordinator of the Network and Wess as co-ordinator of the Scientific-Advisory Committee (SAC) for the network (Djordjević 2012).
The most complex meeting of the network was the Balkan Summer Institute (BSI2011) with 180 participants and four associated events
While singling out the role of individuals might seem disproportionate, it is a pleasure to underline the role of Boyka Aneva in motivating colleagues from Sofia, Mihai Visinescu for those from Romania, Goran Senjanović of ICTP for his service as co-ordinator of the Network SAC (2008–2013) and the first and the current presidents of the Representative Committee of the SEENET-MTP Network, Radu Constantinescu of Craiova (2009–2013) and Dumitru Vulcanov of Timisoara, respectively. Starting in 2003 with 40 members and three nodes in Niš, Sofia and Bucharest, the network has grown steadily to its current size, now covering almost all of the countries in the Southeastern European region plus Ukraine. The Balkan Workshops series is an important part of the SEENET-MTP programme (see box). The most complex meeting of the network was the Balkan Summer Institute (BSI2011) with 180 participants and four associated events.
The main goals of the network and its activities and results can be summarized as follows.
• To organize scientific and research activities in the region and the improvement of interregional collaboration through networking, the organization of scientific events and mobility programmes. The network has organized 15 scientific meetings (schools and workshops) and supported an additional 10 events. Around 1000 researchers and students have taken part in these meetings. Through UNESCO projects, followed by the ICTP project “Cosmology and Strings” PRJ-09, there have been more than 200 researcher and student exchanges in the region, about 150 seminars and 100 joint scientific papers. In co-operation with leading publishers both in the region and the rest of the world, the network has published numerous proceedings, topical journal issues and two monographs. It has also implemented 15 projects, mainly supported by UNESCO, ICTP and German foundations.
• To promote the exchange of students and encourage communication between gifted pupils motivated towards natural sciences and their high schools. Three meetings and contests in the “Science and society” framework have been organized in Romania with 100 high-school pupils and undergraduate students. The network was a permanent supporter and driving force in establishing and supporting the first class for gifted high-school pupils in Niš, Serbia, and its networking with similar programmes.
• To create a database as the foundation for an up-to-date overview of results obtained by different research organizations and, through this, the institutional capacity-building in physics and mathematics. The SEENET-MTP office in Niš, established in 2009, in co-operation with the University of Craiova and UNESCO Venice office, set up the project “Map of Excellence in Physics and Mathematics in SEE – the SEE MP e-Survey Project”. It has collected a full set of data on 40 leading institutions in physics and mathematics in seven Balkan countries.
BW2013: 10 years of the network
This year’s Balkan workshop – BW2013 Beyond the Standard Models – was held on 25–29 April in Vrnjačka Banja, Serbia, just like the first one. The meeting also provided an opportunity to mark 10 years of the network, which now consists of 20 institutions from 11 countries in the region and has 14 partner institutions and more than 350 individual members from around the world. It was organized by the Faculty of Science and Mathematics and SEENET-MTP office, Niš, in co-operation with the CERN Theory Group, the International School for Advanced Studies (SISSA) and ICTP, with the Physical Society Niš as local co-organizer.
The workshop offered a platform for discussions on three topics: beyond the Standard Model, everyday practice in particle physics and cosmology, and regional and interregional co-operation in science and education. The first two days were devoted to purely scientific problems, including new trends in particle and astroparticle physics: theory and phenomenology, cosmology (classical and quantum, inflation, dark matter and dark energy), quantum gravity and extra dimensions, strings, and non-commutative and non-archimedean quantum models. It was an opportunity to gather together leading experts in physics and students from the EU and Eastern Europe to discuss these topics. The third day was organized as a series of round tables on building sustainable knowledge-based societies, with a few invited lecturers and moderators from the Central European Initiative (CEI), UNESCO, the European Physical Society (EPS) etc.
In total, 78 participants from 25 countries came to the events. Around 30 invited scientific talks, 15 panel presentations and several posters were presented. The EPS president John Dudley, EPS-CEI chair Goran Djordjević and former EPS presidents Macie Kolwas and Norbert Kroó were among the panellists. Mario Scalet (UNESCO Venice), Fernando Quevedo (ICTP), Luis Álvarez-Gaume, Ignatios Antoniadis and John Ellis (CERN), Alexei Morozov (ITEP, Moscow), Guido Martinelli (SISSA), Radomir Žikić (Ministry of Education and Science, Serbia) and others contributed greatly to the overall discussion and decisions made towards new projects. Dejan Stojković (SUNY at Buffalo) was unable to attend but has contributed a great deal as lecturer, adviser and guest editor in many network activities. Under the aegis and with the support of the EPS, the first meeting of the EPS Committee of European Integration (EPS-CEI) took place during the workshop and the first ad-hoc consortium based on the SEENET-MTP experience for future EU projects established.
SEENET-MTP: main network meetings
• BW2003 Workshop, Vrnjačka Banja, Serbia
• BW2005 Workshop, Vrnjačka Banja, Serbia
• MMP2006 School, Sofia, Bulgaria
• BW2007 Workshop, Kladovo, Serbia
• MMP2008 School, Varna, Bulgaria
• SSSCP2009 School, Belgrade-Niš, Serbia
• EBES2010 Conference, Niš, Serbia
• QFTHS2010 School and Workshop, Calimanesti, Romania
• BSI2011 Summer Institute, Donji Milanovac, Serbia
• QFTHS2012 School and Workshop, Craiova, Romania
• BW2013 Workshop, Vrnjačka Banja, Serbia
Despite the unexpected success of the SEENET-MTP initiative, its future faces challenges: to provide a mid-term and long-term financial base through EU funds, to prove its ability to contribute to current main lines of research, to extend the meeting’s activities from Bulgaria, Romania and Serbia and to other countries in the network, to organize a more self-connected and permanent training programme through topical one-week seminars for masters and PhD students in its nodes and, possibly in the future, joint masters or PhD programmes.
SEENET-MTP and physicists in the SEE region still need a partnership with leading institutions, organizations and individuals, primarily from Europe. In addition to LMU/MPI, the role of which was crucial in the period 2000–2009, and the long-term partners UNESCO and ICTP, the most promising supporters should be EPS, SISSA and CEI, as well as the most supportive one in the past few years – CERN and its Theory Group.
The Institute for High Energy Physics (IHEP), Protvino, was established as a new Soviet particle-physics laboratory 50 years ago in November 1963. Four years later, the 70-GeV proton synchrotron U-70 – which became known as the “Serpukhov accelerator” – was commissioned, reaching a world-record proton energy of 76 GeV on the night of 14 October 1967. Physics research started at the beginning of 1968, conducted by several groups with unprecedented international participation for that time, in teams from CERN and the French Atomic Energy Commission (the CEA).
Only four years had passed since the theoretical proposal of quarks as elementary constituents of matter, so searching for them in the new energy range became one of the top priorities for the experiments at the U-70. Free quarks were not found but this negative result appears to have been the first of a long list from similar attempts that resulted finally in the well-known hypothesis of quark confinement.
Meanwhile, among many interesting new results that were obtained at the IHEP accelerator during its first years of operation, two in particular stand out: discovery of the growth of hadronic cross-sections with energy and the scaling behaviour of hadronic inclusive distributions. It is worth noting that both phenomena are poorly understood still, even in the framework of modern theory.
Today, IHEP is continuing to carry out a programme of fundamental research at the U-70 in the areas where the accelerator’s parameters offer the opportunity for significant outcomes. In particular, the upgrade of the accelerator complex for higher intensity will create a unique beamline of separated K mesons and a new experimental facility OKA for an extensive programme of research with kaons.
The current physics research programme covers a variety of topics. The spectroscopy of mesons and baryons is served by several experimental facilities: VES, SVD, HYPERON and MIS-ITEP. The search for rare decays of K mesons and for CP violation is the focus for ISTRA+ as well as for OKA. The study of the structure of nucleons takes place with polarized beams in the Spin Asymmetry in Charm production (SPASCHARM) experiment and the FODS double-arm spectrometer, while FODS also investigates hard processes. Last, the SPIN experiment is looking at the properties of baryonic matter. In theoretical particle physics, the main achievements and current activities of the IHEP physicists are related to the physics of heavy quarks, strong interactions at high energies, quantum field theory, gravitation and cosmology.
Alongside the fundamental physics research, IHEP also undertakes extensive studies in accelerator physics and technology. Here, the principle and techniques of radio-frequency quadrupole (RFQ) acceleration proposed and developed at IHEP have been one of the notable achievements in accelerator science. IHEP also put forward the use of bent-crystal deflectors for the extraction of particle beams and for collimation. This technique is now widely used at the U-70 accelerator as well as at Fermilab and at CERN.
An important recent achievement at the U-70 was the commissioning in 2010 of stochastic slow beam extraction, which has significantly improved the performance of the machine and increased the efficiency of the experiments. Since 2011, the U-70 has been upgraded to accelerate carbon nuclei to 24.1–34.1 GeV per nucleon. This has allowed IHEP to proceed with experiments in the field of fixed-target relativistic nuclear physics.
In the area of applications, in 2004–2010 IHEP developed and constructed a unique proton radiography facility, which has been successfully used in co-operation with physicists from the All-Russian Research Institute of Experimental Physics (VNIIEF) in Sarov. In 2011, the U-70 received a new slow-extraction system at flat bottom, which delivers a beam of carbon nuclei at 450–455 MeV per nucleon for applied research.
Last but not least, IHEP contributes significantly in broad international collaborations with CERN, Fermilab and Brookhaven National Laboratory. Examples include the production of an endcap muon wall for the DØ experiment at Fermilab’s Tevatron, an electromagnetic calorimeter for the PHENIX experiment at Brookhaven’s Relativistic Heavy-Ion Collider, electrical feedboxes, dump resistors, septum magnets and beam-loss monitors for CERN’s LHC, monitored drift-tube chambers and tiles for hadron calorimetry in the ATLAS detector at the LHC, crystals for electromagnetic calorimetry in the CMS experiment, and modules for LHCb’s hadron calorimeter. IHEP is also a Tier-2 site in the Wordwide LHC Computing Grid.
Paris, dans les années 1950. Michel a 11 ans et voit des bulles, ce dont il est très fier. Terme résolument non scientifique, le mot ” bulle ” désigne pour le narrateur – Michel – ” une myriade de points lumineux dansant dans tous les sens “, points lumineux qui se révèleront être, au fil des pages, des ” neutrinos “. Nous y voilà.
Vous l’aurez compris, bien qu’écrit par un physicien des particules spécialisé en physique des neutrinos, ce livre est un roman. L’objectif n’étant pas de vous en apprendre des kilomètres sur ces fameux neutrinos, mais de vous embarquer dans une histoire dont ils sont les protagonistes. Et si l’histoire est contée par un jeune narrateur passionné de physique, il n’en reste pas moins qu’il s’agit d’un enfant, et non pas (encore) d’un physicien des particules.
L’intrigue, si je puis donner à l’histoire cette connotation très romanesque, est somme toute assez simple. Michel, écolier plutôt mauvais en maths mais bon en imagination, vit dans un minuscule appartement parisien avec ses parents. Il va à l’école à pied, troue ses chaussettes, accompagne sa mère au marché le jeudi et à la messe le dimanche, passe ses vacances d’été à la campagne, collectionne les timbres, adore les truffes au chocolat, et se délecte des histoires de science de son oncle Albert, fonctionnaire tire-au-flanc et lecteur assidu de magazines de vulgarisation scientifique. Mais ce qui anime surtout Michel, moins son histoire, c’est cette étrange capacité à voir des neutrinos.
Mais ne vous méprenez pas, les neutrinos de Michel sont loin de coller à l’idée que l’on s’en fait au CERN. Pour Michel, ce ne sont en effet ni plus ni moins que les constituants de l’âme des êtres vivants, ou, comme les décrit encore le narrateur, ” notre carburant spirituel “. Ce qui explique d’ailleurs que les jeunes en émettent plus que les vieux, et que ceux qui n’en émettent plus sont morts. CQFD.
Au final, ce livre est un long voyage dans la tête d’un gamin de 11 ans, à la rencontre de ses idées farfelues, de ses expérimentations et déductions scientifiques, de ses découvertes triomphantes et de ses confrontations au monde des adultes. Certains passages sont franchement réjouissants, et l’on finit par se prendre d’affection pour le jeune Michel, qui garde précieusement au fond de sa poche, un marron, une bille et une boîte pleine de neutrinos.
By Alexander W Chao and Weiren Chou (eds.) World Scientific
Hardback: £98
E-book: £74
Reviews of Accelerator Science and Technology is a journal series that began in 2008 with the stated aim “to provide readers with a comprehensive review of the driving and fascinating field of accelerator science and technology” – in a “journal of the highest quality”. It made an excellent start, with the first volume presenting the history of accelerators, followed by one that focused on medical applications. With one volume published a year, there are now five in the series, which appears to show no signs of failing in its original goals. Each has communicated a specific topic through the words of highly respected experts in articles that are well illustrated and presented. The books they form hold the promise of becoming an unrivalled encyclopaedia of accelerators.
This latest volume is no exception. It looks at the role of superconductivity in particle accelerators and how this intriguing phenomenon has been harnessed in the pursuit of ever-increasing beam energy or intensity. It also considers the application of superconducting technology beyond the realm of accelerators, for example in medical scanners and fusion devices. As well as containing much technical detail it is also full of fascinating facts.
Exactly 100 years ago, Heike Kamerlingh Onnes speculated that a 10 T superconducting magnet “ought not to be far away”. The first contributions to this volume, in particular, outline some of the steps to 10 T – and why it took longer than Onnes had originally hoped for the industrial-scale production of high-field superconducting magnets to become reality. A major problem lay in finding superconducting materials with physical properties that allow large-scale fabrication into wires. The first commercially produced wires were of niobium-zirconium, as used in early superconducting magnets for bubble chambers. However, this alloy was soon superceded by niobium-titanium (NbTi) – the material of choice in high-energy physics for the past 40 years, culminating today in the superconducting magnets for the LHC, as well as the huge toroidal and solenoidal magnets for the ATLAS and CMS detectors. Now, R&D effort is turning to Nb3Sn, which can allow higher magnetic fields, for example for the High Luminosity LHC project.
In this context, it is worth realizing that the biggest market for superconducting magnets is for nuclear magnetic-resonance spectroscopy – and it is here that a field as high as 23.5 T has been reached in a magnet based on Nb3Sn. There is also interest in high magnetic fields for magnetic resonance imaging (MRI) in medicine. In MRI the signal strength is related to the polarization of the protons in whatever is being scanned. Increasing the magnetic field from the 1.5 T that is currently used routinely to 10 T results in a polarization that is almost seven times higher, as well as improved signal-to-noise, leading to a clear improvement in image quality. Upcoming developments include 6 T magnets based on Nb3Sn.
The application of superconductivity in particle accelerators extends of course to the acceleration system, with the use of superconducting RF technology, first proposed in 1961. In this case, an important part of the R&D has focused on the physics and materials science of the surface – the surface resistance being a key parameter. So far there are no commercial applications for superconducting RF, but it has a role in many types of particle accelerators, from high-current storage rings at light sources to the high-energy machines of the future, such as the International Linear Collider (ILC).
Jefferson Lab’s Continuous Electron-Beam Accelerator Facility (CEBAF) is in a sense the “LHC” of superconducting RF, employing originally 360 five-cell 1.5 GHz cavities. It is currently undergoing an upgrade to 12 GeV with cavities that will operate at 19.2 MV/m. The European X-ray free-electron laser project, XFEL at DESY, will use 800 nine-cell 1.3 GHz cavities operating at more than 22 MV/m, but it would be dwarfed by an ILC with more than 15,000 cavities.
Besides the contributions on the major topics of superconducting magnets and RF, others are dedicated to cryogenic technology, industrialization and applications in medicine. In addition, following the journal’s tradition, there are articles that are not related to the overall theme but are of concern to the accelerator community worldwide. In this case, one article discusses the education and training of the next generation of accelerator physicists and engineers, while another reviews the history of the KEK laboratory in Japan. Altogether, this makes for more than a journal volume – in my opinion, it is a book, well worth reading.
By Martin H Krieger Indiana University Press
Paperback: £16.99 $24.00
E-book: £14.99 $21.99
First published over two decades ago, Doing Physics has recently been released as a second edition. The book relates the concepts of physics to everyday experiences through a carefully selected series of analogies. It attempts to provide a non-scientific description of the methods employed by physicists to do their work, what motivates them and how they make sense of the world.
Martin Krieger began his academic career in experimental particle physics but quickly realised that he was not suited to working in large groups on experiments. Following his PhD, he moved into the social sciences and began working on computing models for city planning. He uses this experience to reflect on the way science is done from a social science viewpoint. His aim is to explain how doing physics is part of familiar general culture.
Krieger claims that physicists employ a small number of everyday notions to “get a handle on the world” experimentally and conceptually. He argues further that these models and metaphors describe the way physicists actually view the world and that to see the world in such terms is to be trained as a physicist. The analogies he chooses to support his ideas are drawn from the diverse areas of economics, computing, anthropology, theatre and engineering. Each of the first five chapters of the book is devoted to exploring each of the analogies in detail.
The book begins with a discussion on division of labour according to the economist Adam Smith’s model of a pin factory. The description of physical situations in terms of interdependent particles and fields is analogous to the design of a factory with its division of labour among specialists. The second chapter considers physical degrees of freedom as the parts of a complex model such as a clockwork mechanism or a computer. Chapter three is devoted to the anthropological theory of kinship and marriage, comparing the rules of relationships to the rules of interaction for the families of elementary particles or for chemical species – who can marry whom is like what can interact with what. The conclusion is that anything that is not forbidden will happen. The theatrical world provides an analogy to creation, where a vacuum is represented by a simple stage setting on which something arises out of nothing. Finally, machine-tool design is used to describe the physicist’s toolkit, where the work of doing physics is like grasping the world with handles and probes.
In the second edition, Krieger has provided some minor revisions to the text and has added a brief chapter on the role of mathematics and formal models in physics. This additional discussion is based on work from two other books he has written in the intervening years. It is questionable whether the second edition is warranted. In this highly technical chapter Krieger goes so far as to discern an analogy of analogies in physics and mathematics – a so-called syzygy.
Krieger claims that the book is for high-school students and upwards. However, it seems more appropriate for a specialized audience. Doing Physics is aimed at sociologists and philosophers of science, rather than at the science community itself. Indeed, for some the experience of reading the book could bring to mind a well known quote by Richard Feynman: “Philosophy of science is about as useful to scientists as ornithology is to birds.” For others, however, the book might provide some useful insights into patterns or relationships between physics and the everyday world that they have not previously considered.
François Englert, left, and Peter W Higgs have been awarded the 2013 Nobel Prize in Physics “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN’s Large Hadron Collider”. The announcement by the ATLAS and CMS collaborations took place at CERN on 4 July last year.
In mid-September, the Long Baseline Neutrino Experiment (LBNE) collaboration, based at Fermilab, welcomed the participation of 16 additional institutions from Brazil, Italy and the UK. The new members represent a significant increase in overall membership of more than 30% compared with a year ago. Now, more than 450 scientists and engineers from more than 75 institutions participate in the LBNE science collaboration. They come from universities and national laboratories in the US, India and Japan, as well as Brazil, Italy and the UK.
The swelling numbers strengthen the case to pursue an LBNE design that will maximize its scientific impact. In mid-2012, an external review panel recommended phasing LBNE to meet the budget constraints of the US Department of Energy (DOE). In December the project received the DOE’s Critical Decision 1 (CD-1) approval on its phase 1 design, which excluded both the near detector and an underground location for the far detector. However, the CD-1 approval explicitly allows for an increase in design scope if new partners are able to contribute additional resources. Under this scenario, goals for a new, expanded LBNE phase 1 bring back these excluded design elements, which are crucial to execute a robust and far-reaching neutrino, nucleon-decay and astroparticle-physics programme.
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