School looks forward to ep and eA colliders

The International Spring School "QCD prospects for future ep and eA colliders", organized in the framework of the "Groupement de Recherche Chromodynamique Quantique et Physique des Hadrons", took place at the Laboratoire de Physique Théorique, Orsay, on 4–8 June. The aim was to bring together PhD students, postdocs and tenured physicists, both theoreticians and experimentalists, whose main interest relates to the strong interaction in nuclear and particle physics and its fundamental theory, QCD. A total of 64 participants came from Europe (Belgium, Italy, France, Germany, Spain) and the US and – as intended – an informal atmosphere generated fruitful exchanges between the lecturers, students and postdocs, as well as between experienced physicists.

The scientific programme was constructed with a view to developing the skills of the students and postdocs in mastering the various theoretical and experimental challenges raised by the different electron–proton and electron–ion collider projects that are currently under study in Europe and the US. To do this, it focused on several key topics, in the spirit of an ideal machine that would combine a high centre-of-mass energy, high luminosity and beam-polarization facilities. Although covering mainly phenomenological and theoretical issues, the programme also touched on the experimental aspects of the different projects.

The four main lecturers, some of the leading experts in the field, were given a substantial amount of time to cover the various topics of this multifaceted domain in an extensive way. George Sterman of Stony Brook University gave his vision of the factorization of hard processes in QCD. In a dense and rather demanding series of lectures, the audience explored with him the fascinating aspects of pinching singularities and their physical meaning, from scalar to Yang-Mills theories, including the use of Ward identities. Some aspects in particular were covered in an advanced school for the first time.

Alfred Mueller of Columbia University gave an overview of the most striking effects of QCD dynamics at asymptotical energies in which he emphasized the saturation of quarks and gluons. He relied particularly on his dipole model, a multicolour version of QCD formulated in the light-cone perturbation theory, which has a rich dynamics with an illuminating physical content.

Piet Mulders of VU University, Amsterdam, presented the new concept of transverse-momentum-dependent parton distributions (TMDs) and their interest for gaining access to the spin content of the nucleon. He emphasized the factorization properties of processes such as semi-inclusive deep-inelastic scattering in terms of these TMDs. The issues of potential breaking of factorization with universal time-odd TMDs were discussed at length.

Last, Marc Vanderhaeghen of the University of Mainz covered various theoretical and phenomenological aspects of the spatial structure of hadrons and generalized parton distributions. These non-diagonal parton distributions occur naturally in deeply virtual Compton scattering. In particular, he gave a comprehensive overview of the physical picture that is now available of the internal structure of hadrons, thanks to the combined efforts of the experimental and theoretical community over the past decade.

Two shorter lectures on the projects for the Electron–Ion Collider and the Large Hadron–electron Collider were given by Franck Sabatié of l’Institut de Recherche sur les lois Fondamentales de l’Univers (Irfu) and Néstor Armesto of the University of Santiago de Compostela. They showed clearly that these challenging projects could have a major impact on the understanding of hadron structure, at both a qualitative and a quantitative level, with complementary aspects related to the medium- and high-energy ranges that the colliders would cover. A lecture on jet physics by Leandro Almeida of l’Institut de Physique Théorique, Saclay, completed the programme and some of the PhD students and postdocs gave seminars on their recent work.

The school was financially supported by the Labex P2IO, the GDR PH-QCD, the Université Paris Sud, the CNRS, the CEA/Irfu and the Joint Research Activity "Study of Strongly Interacting Matter" HP3. Thanks to this support, several PhD student obtained a partial cover of their expenses.

• For more information about the school, see http://indico.in2P3.fr//event/QCD-ep-eA-colliders.


Caterina Biscari to head ALBA facility

Caterina Biscari has been appointed director of the CELLS consortium, which constructed and now operates ALBA, the third-generation synchrotron light source near Barcelona. Appointed by the consortium’s governing council, she takes over from acting director Gastón García from September. The ALBA facility has been in operation since March this year, providing synchrotron light for a range of experiments (CERN Courier November 2008 p31).

Biscari was previously technology director and scientific deputy of the Accelerators Division at INFN’s National Laboratory of Frascati. She has worked in several laboratories around the world, including CERN and most recently at the Centro Nazionale di Adroterapia Oncologica in Pavia. Now a fellow and executive committee member of the of the European Physical Society, she has also been chair of the society’s Accelerator Group and is a member of the Machine Advisory Committee for the LHC.


Calorimetry aficionados meet in Sante Fe

The XVth International Conference on Calorimetry in High Energy Physics, CALOR2012, took place in Santa Fe, New Mexico, on 4–8 June. This series of conferences started in 1990 at Fermilab and has been the premier event for calorimeter aficionados, a trend that CALOR2012 upheld. This year, several presentations focused on the status of major calorimeter systems, especially at the LHC. Discussions on new and developing techniques in calorimetry took a full day. Excellent updates on uses of calorimeters or ideas that are deeply rooted in particle-physics calorimetry in astrophysics and neutrino physics were followed by talks on algorithms and special triggers that rely on calorimeters. Last, discussions of promising current developments and ongoing R&D work for future calorimeters capped the conference. The field is alive and well, as demonstrated by the more than 100 attendees and the excellent quality of the 80 presentations.

The first day of the conference was dedicated to the LHC. In two invited talks, CERN’s Guillaume Unal and Tommaso Tabarelli de Fatis of INFN/University of Milano-Bicocca discussed the critical role of the electromagnetic calorimeters in the hunt for the Standard Model Higgs boson in the ATLAS and CMS experiments, respectively. With much of the higher mass-region excluded for the Standard Model Higgs, the enhanced sensitivity for light Higgs in the two-gamma decay channel render electromagnetic calorimeters indispensable. Both of the speakers reported exceptional performance and overall control of detector systematics, even in the increasingly harsh environment at 8 TeV in the centre of mass. In the case of CMS, for example, precise intercalibration of towers, stabilization of environmental effects and corrections for uniform response in more than 75,000 lead-tungstate crystals result in much less than 1% constant term in energy resolution. The measurement of missing transverse energy and jet energy-scale corrections in ATLAS and CMS were also presented in several talks.

Calorimetry is extremely diverse: many different techniques may be employed in building the detector and also in extracting information from it. The topics of the Calorimeter Techniques sessions included high-rate liquid-argon calorimeters, silicon photomultiplier sensors, highly granular digital calorimeters, new crystals and beam-test and simulation results. Don Groom of Lawrence Berkeley National Laboratory presented an intriguing study on why a homogenous dual-read-out calorimeter is unlikely to work.

Although natural media such as water would hardly be choice absorbers in accelerator-based experiments, they are nevertheless successfully exploited in searches for new phenomena. Members of the Telescope Array (Utah air), ANTARES (Mediterranean water) and ARA, ARIANNA, ANITA and other (Arctic ice) collaborations discussed their use in several talks. Invited speaker, Philippe Bruel of the Laboratoire Leprince-Ringuet, Ecole Polytechnique, gave an overview of the gamma-ray sky above 20 MeV using the Fermi Gamma-ray Space Telescope and the role of the hodoscope array of the CsI(Tl) calorimeter. In a second invited presentation, Sylvie Rosier-Lees of the Laboratoire d’Annecy-le-Vieux de physique des particules described the design of the electromagnetic calorimeter (Pb/scintillating fibre sandwich) for the Alpha Magnetic Spectrometer (AMS-02), which has been operating in the International Space Station since May 2011 (AMS experiment marks one year in space) and has already collected more than 15 billion events.

In addition to making advances in calorimeter design, hardware and front-end electronics, particle physicists are increasingly finding themselves inventing new algorithms to reconstruct physics objects that use the detector information to its maximum capacity. Several presentations provided details on the reconstruction and trigger of jets, missing transverse energy, electrons, photons and τ leptons. Pile-up, anomalous signals and noise-mitigation techniques were also discussed in the conference.

The last day saw the presentations of several future R&D initiatives, in particular for a future linear collider. The highly granular CALICE project, with different technology options, and plans for the dual-read-out DREAM project, were the main topics. Although these approaches are quite different conceptually, future experiments will certainly benefit from their innovations.

Several events allowed participants to share their interest in other topics. A rare astronomical event – the transit of Venus – coincided with the second day of the conference. The participants enjoyed viewing Venus’ trail across the Sun with a solar telescope (H-alpha line at 656 nm). In Santa Fe, the interior ingress was at 16:23:04 MST (GMT–7) and reached centre at 19:27:04 MST. The last transit occurred in 2004 and the next one will happen in 2117.

The environs of Santa Fe have long been considered sacred by the indigenous Americans and have been a source of inspiration for generations of artists, writers and scientists. Robert Oppenheimer’s love of this area played no small role in establishing, during the Second World War, what is now the nearby Los Alamos National Laboratory. On the third day of the conference, some participants visited the lab after an awe-inspiring trip to the Bandelier National Monument, where canyons and mesas show evidence of a human presence going back 11,000 years.

In the 1980s, scientists mainly from Los Alamos set up the Santa Fe Institute, famed for its interdisciplinary research. Geoffrey West of the institute gave the keynote address. His talk, "Universal scaling laws from cells to cities – a physicist’s search for quantitative, unified theories of biological and social structure and dynamics", inspired many interesting questions from the audience both after the talk and throughout the week during informal conversations.

CALOR2012 concluded with remarks by the chair of the organizing committee, Nural Akchurin of Texas Tech University. He summarized the highlights of the conference and invited proposals to host the CALOR2014 conference in Europe. The conference venue rotates between the Americas, Europe and Asia every two years.

• The CALOR12 presentations can be found at calor2012.ttu.edu and the proceedings will be published by IOP (Journal of Physics Conference Series) in the autumn.


JINR calls for nominations for Flerov prize

The Joint Institute for Nuclear Research, Dubna, has announced the contest for the 2013 G N Flerov Prize for outstanding achievements in nuclear physics, which will be awarded in March 2013, on the centenary of the birth of the eminent Russian physicist, Georgy Nikolaevich Flerov. The prize was established in 1992 in memory of Flerov and rewards contributions to nuclear physics related to his interests. The contest is for individual participants only.

For the centenary year, in which two prizes will be awarded, the Flerov Prize board invites both individual submissions and nominations by the former winners of the prize and by distinguished scientists in low-energy heavy-ion physics, nuclear chemistry and applied nuclear research. Entries for the 2013 prizes should include a CV, an abstract of research and copies of major contributions. These should be sent by 1 February 2013 to: Sergey Sidorchuk, Scientific Secretary of the Flerov Laboratory of Nuclear Reactions, Joliot Curie str. 6, 141980, Dubna, Moscow Region, Russia; or by e-mail to sid@nrmail.jinr.ru.