C: NEUTRINO OSCILLATIONS: K2K EXPERIMENT, NEUTRINO FACTORY R & D 1 Summary

26 C: NEUTRINO OSCILLATIONS: K2K EXPERIMENT, NEUTRINO FACTORY R & D

Collaborators: Alain Blondel (PO), Anselmo Cervera (MA), Edda Gschwendtner, puis Jean-Sebastien Graulich (MA), M. Campanelli (part- time), Silvia Borghi (A), Gersende Prior (A), Rikard Sandström (A), Raphaël Schroeter (A), Olena Voloshyn (DEA Student) and Nicolas Abgrall (Master student) (2004-2005); technical team (electronics, computing and mechanics) from DPNC: Jean-Pierre Richeux, Pierre Béné, Eric Perrin, Florian Masciocchi, Yann Meunier.

1 Summary

The activities of the group in the year 2004-2005 have been as follows: Participation in the calibration, software and analysis of the HARP experiment (A. Blondel, S. Borghi, A. Cervera, G. Prior, R. Schroeter); the first publication from HARP (forward analysis in view of the K2K experiment) has now been published, with several others being prepared with the forward analysis; the TPC calibration is at a satisfactory state and the analysis is nearing completion. The HARP activities lead naturally to a participation in the Japanese neutrino program, with the experiment K2K (A. Blondel, S. Borghi, A. Cervera, R. Schroeter); observation of oscillations from an accelerator-based neutrino beam, and physics results from the near detector station. Preparation of the T2K experiment. We participate in the design and prototyping of the tracking detector (a TPC with GEM or micromegas readout) for the near (280m) detector station. A prototype chamber was built at University of Geneva and the first results were recently obtained (A. Blondel, A. Cervera, R. Schroeter, N. Abgrall). Management of the ECFA/BENE EU sponsored study groups and of the European R&D (A. Blondel), and initiation of the International Scoping Study (ISS). Preparation of the muon ionization cooling experiment MICE at Rutherford Laboratory (A. Blondel – spokesperson of the experiment, E. Gschwendtner then J.-S. Graulich, R. Sandström, O. Voloshyn). The first phase of the experiment is now fully funded. We play an important role in the simulation of the experiment, in particular emission of electrons by the RF cavities and particle identification detectors. We have developed a TPC with GEM read-out as a low material tracker option, and are now leading the DAQ effort for the TOF and calorimeter. Dissemination and outreach, with several invited conferences and organization of public conferences on the occasion of CERN’s 50th anniversary and year of physics, active role in the CHIPP activities.

27 2 HARP and K2K

The physics objective of HARP1 is a systematic and precise study of hadron production for beam momentum between 2 and 15 GeV/c for target nuclei ranging from hydrogen to lead. Existing data in this energy range is usually old and spans over limited parts of phase space. The experiment was approved on 17 February 2000 and began to take data with a complete apparatus by August 15 2001. The data taking was completed in November 2002 with a great variety of beams and targets. The expedience to install and run the experiment has been compensated by a rather long period of understanding the data and performing calibrations and corrections. Nevertheless, the first paper2 was accepted for publication in October 2005.

Figure 1 Overall view of the HARP experiment at CERN

2.1 TPC Calibration and reconstruction

The TPC was built in 17 months and the data taking took place before the detector was fully understood, thus many ‘effects’ had to be taken care of by after-the-fact calibrations. A run of calibration and cosmic data was taken in summer 2003. In June 2004 a concentrated effort was launched in order to conclude these efforts and to produce a consistent set of calibrations with the necessary software algorithms. Silvia Borghi performed most of this work, as well as participating in the calibration of the RPCs. A great number of issues were resolved: time calibration (see enclosed note3), cross-talk corrections, pad response equalization and dead- channel mapping, etc. However, much of the difficulties and work lied in the electromagnetic distortions.

The implementation of static corrections as understood from cosmic data, is now complete and improved the resolution by a factor 2. The effect of dynamic distortions, observed by A. Blondel, C. Morone and S. Borghi, remained to understood. These appear as a time dependent offset in the average impact parameter of tracks, as revealed to the collaboration by S. Borghi in November 20044, and shown in Figure 2. The interpretation is that charge builds up in the chamber with time. The charge density is roughly inversely proportional to the radius but the exact distribution is unknown. Thus the proper resolution can be recovered by selecting data at the beginning of the spill and an approximate correction can be made for the rest. 28

Figure 2: The mean d0 for positive(red) and negative (blue) tracks as function of the event number in the spill after correction for static distortions. The non-zero values at N>50 is a clear sign of the building up of EXB effects.

Figure 3: Results from the HARP TPC. Top left: missing mass distribution in the hydrogen target run,with selected proton beam,showing the elastic scattering peak; right dE/dx distribution of particles in the elastic peak showing the proton and pion bands. Bottom left; ibid after a selection for dE/dx has been made for protons; right:ibid for beam pions. This reaction will be used for absolute momentum calibration.

Encouraging results on the dE/dx and missing mass resolution for the elastic scattering reaction can be seen in Figure 3 and described in detail in ref 5. It is now expected that the momentum and angle distribution and cross-section of pions produced on various targets will be produced for S. Borghi’s thesis before the end of 2005, as input to the optimization of the 29 energy of the next high intensity proton accelerator at CERN. Preliminary results have already been produced, as shown in Figure 4.

Figure 4 Preliminary results for the Large angle pion production differential cross-sections from 3 GeV/c protons on Tantalum target.

2.2 HARP forward spectrometers and Analysis of the K2K replica data

The systematic error in the determination of oscillation parameters in the K2K experiment is presently dominated by extrapolation from the near to the far detector and depends critically on the hadron production model. Special runs were taken by HARP reproducing the exact K2K conditions, 12.9 GeV/c incident proton beam on a 80 cm long aluminum target. The relevant kinematical region coincides with the forward spectrometer of HARP. We actively participated in the development of track and PID reconstruction algorithms in the forward region, which includes a set of drift chambers, a time of flight, a threshold Cherenkov and an electromagnetic calorimeter, allowing particle identification as shown in Figure 5, Figure 6 and Figure 7. 30

Figure 5 Number of photo-electrons measured in the HARP forward Cherenkov for negative particles below (left) and above(right) the pion Cherenkov threshold.

Figure 6 measurement of the HARP forward electromagnetic calorimeter response for particles below pion Cherenkov threshold, with(left) and without (right) more than 15 photo-electrons in the Cherenkov. The population of electrons (from photon conversions) is clearly visible on the left.

Figure 7 Hadron identification with the HARP time of flight counters: left, positive particles with momentum between 1.75 and 2.25 GeV/c; right, positive particles with momentum between 3.25 and 4 GeV/c. Populations of protons, kaons and pions are clearly visible. Anselmo Cervera leads this work in the collaboration. He presented the first results from HARP at the Moriond conference in March 2004. The full analysis of positive pion production in the K2K replica was published in October 20052. The particle spectra are shown in Figure 8. 31

Figure 8 positive pion production spectra in bins of momentum and angle for the K2K replica.

Figure 9 Muon neutrino fluxes in the K2K experiment as a function of neutrino energy Eο, as predicted by the + default hadronic model in the K2K beam Monte Carlo simulation (dotted histograms),and by the HARP θ production measurement (filled circles with error bars). Left: unit-area normalized flux predictions at the K2K near (top) and far (bottom) detector locations, Γ near and Γ far; right : the far–to–near flux ratio (empty squares with error boxes show the K2K model results), showing the precision improvement brought by the HARP data.

The resulting improvements are shown in Figure 9 . Raphael Schroeter has already achieved his Diploma thesis on the issue of use of HARP data in the K2K analysis. The layout of the K2K experiment is shown in Figure 10.

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Figure 10 The K2K experiment in Japan. The neutrino beam is generated by a 12.9 GeV/c proton beam at KEK and monitored in near detectors. It is aimed at the Super Kamiokande detector 250 km away. The solid angle seen by the near detectors is different from that of Super Kamiokande and requires a correction (far to near ratio), shown on the right. The oscillation maximum is around ~500 MeV neutrino energy; below 1 GeV the beam monitoring is ineffective and precision hadron production data are necessary.

Strange particle production in the forward direction is an important piece of the puzzle, when trying to determine the electron neutrino background in the muon neutrino beam, since Ke3 decays of neutral and charged Kaons constitute an irreducible background in the search ον!↓ οe oscillations. The measurement of neutral Kaon production was the theme of the PhD thesis of Gersende Prior, and the measurement of charged kaon production will be the theme of the PhD thesis of Raphaël Schroeter. As shown in Figure 7, the kaon production in the forward spectrometer is clearly visible.

2.3 K2K Physics results

After a long shut down to repair the damage to the Super Kamiokande detector caused by the implosion of two third of the 11000 photo-multipliers, the K2K experiment resumed data taking in April 2003, and continued until end 2004. The Geneva group took part in this data taking and in the analysis of the HARP particle production as described above. The data confirmed the previous indications of neutrino oscillation at the same wavelength discovered in atmospheric neutrinos. This was communicated to several conferences and the publication as been published in Physical Review Letters6. The observation of oscillation is now at a level of significance of 4 standard deviations (Figure 11).

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Figure 11 Observation of neutrino oscillation with the K2K experiment. Left: the observed energy spectrum of reconstructed neutrino events in the Super Kamiokande detector. Points with error bars are data, full smooth line is predicted spectrum in absence of oscillation using the calculated flux normalization, full histogram is predicted spectrum in absence of oscillation normalized to the number of observed events, dashed histogram is predicted spectrum for the best oscillation parameter fit. The nearly total disappearance around 500 MeV is 2 2 clearly visible. Right: allowed region of parameter space in the sin 2ρ vs. Εm plane in a two-neutrino oscillation analysis. The three-neutrino oscillation analysis requires input from other experiments but these 2 2 parameters correspond in this case to sin 2ρ23 and Εm 23.

3 The T2K experiment

The logical continuation of the K2K experiment will be the J-PARC-Neutrino program (Figure 12), which will take advantage of several factors: - The newly approved high intensity Japanese Proton Accelerator Research Complex (J- PARC) at Tokai allows the construction of a very intense neutrino beam with improved statistical sensitivity by a factor 100 w.r.t. K2K. The accelerator is now under construction and the proposed neutrino beam is planned to operate in 2009. - The far detector will be the existing Super-Kamiokande detector, which provides good sensitivity to ον !← !οe oscillations when exposed to the J-PARC beam (Figure 13). The T2K (Tokai to Kamioka) experiment was approved in December 2003, including the 280 meter near detector. The beam line is presently under construction. After having signed the letter of intent7, we are preparing our contribution to the experiment. The main design features of the T2K experiment lie in its beam line: 1. The neutrino beam is produced by pion decay from a horn focused beam, with a system of three horns and reflectors. The decay tunnel length (130 m long) is optimized for the decay of 2-8 GeV pions and short to minimize the occurrence of muon decays. 2. The neutrino beam is set at an angle of 2-3 degrees from the direction of the super- Kamiokande detector. 3. The beam line is equipped with a set of dedicated on-axis and off-axis detectors at two different distances, 280 meters, and possibly, at a later stage, 2 km. see Figure 14.

The main goals of the experiment are as follows: 1. The highest priority of the experiment is the appearance search for the yet unobserved ο ←ο neutrino oscillation ν e with the same frequency as the atmospheric oscillation (which is known to be mostly due to ο ν ←ου ). This will manifest itself by appearance of events with an 34 ρ electron in the final state. This reaction is driven by the yet unknown mixing angle 13 , which also drives the CP violation asymmetry which could be observed in the same channel by comparing neutrino oscillations to antineutrino oscillations. The main challenge is the understanding of the backgrounds that produce or mimic an electromagnetic shower: beam οe from K and muon decay; θ0 production by neutral current events. The solution is to measure precisely the beam composition and the rate and topology of backgrounds, so as to be able to perform a good simulation of the far detector. Since nuclear effects are rather important (pion absorption in particular), the material should be as near as possible to the water of Super- Kamiokande. A magnetic, fine grain detector situated in the 280m near detector station, where the rate is higher, will be dedicated to these studies. The 280m detector is part of the approved T2K project.

Figure 12: Overview of the J-PARC to SuperKamiokande long baseline experiment foreseen from 2009. Also shown is the K2K beam from KEK to the SuperKamiokande detector.

2 Figure 13: Sensitivity of the T2K experiment to the rare oscillation ον
οe showing sensitivity down to sin ρ13 >0.006 at 95% C.L.

35 2. Disappearance measurements, where the number and rate of ον
!ον events is 2 studied, will improve the measurement of Εm 13 (after MINOS, CNGS) down to a precision of 0.0001 or so (the present preferred value is 0.0024±~.0005). The exact measurement of the 2 maximum disappearance constitutes a precise measurement of sin 2ρ23. These precision measurements of already known quantities require good knowledge of flux shape, absolute energy scale, experimental energy resolution and of the cross-section as a function of energy. It is absolutely necessary here to have a near detector station with material and acceptance as similar as possible to those of the far detector. The flux at the 2km station is much more similar to the SK flux than at 280 m, which constitutes, for this particular physics goal, an argument in favor of a 2km near-detector, as shown in Figure 14. the 2km detector is planned as an upgrade to be considered after the first data taking will have taken place in 2009.

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0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Eν (GeV) Figure 14: Schematic description of the detectors along the T2K beam line. The 280m detector station is part of the approved project. The 2km station is part of a possible upgrade. Right: flux shape from the off-axis neutrino beam at 280 m (blue) 2km (red) of Super-Kamiokande(black).

Figure 15 Cut-away view of theND280 magnetic detector 36 The contribution of the European groups will be in the 280m near detector station. An important contribution is the gift by CERN of the UA1/NOMAD magnet, which was approved by the CERN council in December 2004. The Geneva group is involved in the tracker of the 280m near detector: building on our experience with TPCs (possibly with GEM readout as described later) we propose an important contribution to the tracking system. The 280m detector station is described in detail in the T2K ND280 Conceptual Design Report8 . A 1 sketch is show in Figure 15. Following a θ detector, a tracking system will measure the momentum of the charged particles produced by neutrino interactions. A number of fine grained detectors situated in the middle of the TPC volume should allow a precise selection of the quasi elastic events in which the secondary proton is detected.

Figure 16 Top: sketch of one of the TPC modules for the T2K magnetic 280m near-detector.

A sketch of one of the TPCs to be designed an built is shown in Figure 16. As can be seen, one of the difficulties will be to pave the readout planes without generating cracks. A GEM readout is interesting because it is very cheap, but the issue of the cracks between readout boards and GEMs needs to be addressed and prototyped in detail, as well as the interplay between pad size and the nature of the gas. The HARP magnet (in which we tested successfully the TPG for MICE) offers great opportunity for such tests, being equipped of a field cage and providing a magnetic field which is in the same range as that of the UA1/NOMAD magnet.

In collaboration with the EU groups of Saclay, Barcelona, Bari, (and much help from the CERN-ALICE group) we have built a test prototype with three stages of GEM amplification, as described in Figure 17 , in which two read-out systems are connected side-to-side with a crack of 8mm. The design and construction of the detector itself were performed by the electronics and mechanics groups at University of Geneva, the preamp and ADC electronics was purchased from the CERN ALICE group, with a number of connections and interface cards built at University of Geneva and Barcelona. A number of original solutions were tested, in particular the possibility to subtend the GEMs without spacers, a choice that proved successful and will allow considerable savings in the construction of the final device.

The assembly and HV test of the detector was performed in the clean room at University of Geneva. The detector was then installed in the HARP TPC area and connected. Thanks to the 37 previous experience from HARP, the readout was successful and the first tracks were observed at the end of October 2005.

Figure 17 T2K TPC R&D at university of Geneva and CERN. Top left: Design of the TPC readout module with 3 planes of GEMs and minimized dead space in the connection between GEMs; Top right: a thin film of glue is deposited on the GEM frames, fabricated at UNIGE; Middle left: the assembly and testing area in UNIGE’s clean room; Middle right: the assembled detector at university of Geneva. Bottom left: the detector installed in the HARP TPC magnet and field cage. Bottom right: first cosmic tracks observed in the TPC. 38 Systematic studies of the performance of the detector will now be undertaken, in particular the study of the dependence of the resolution on the gas composition, electric field distortions, and track quality at the vicinity of the crack between GEMs. Much was learned already from this exercise, in particular for what concerns the mechanics of connections of the pad plane and GEM supports.

4 Future neutrino beams

In spite of the spectacular success of the neutrino physics program in Japan, it is essential to pursue the successful undertakings in accelerator R&D in Europe towards Neutrino Facilities. The scenario for the long term neutrino program at CERN involves a high intensity proton source. The leading candidate is at present the SPL, a 3.5 GeV, 4 MW, superconducting Linac with a repetition rate of 50 Hz.

Figure 18 . Two possible set-ups for high quality neutrino beams for the study of oscillations. Left the conventional neutrino beam directly produced by the SPL; right, the ultimate tool, the Neutrino Factory.

One possibility (Figure 18) could be a low energy (around 300 MeV) conventional neutrino beam to e.g. the large underground Fréjus laboratory, where the possible excavation of a large cavern (capable of hosting a 1 Megaton detector) is being studied jointly by France and Italy. 6 ↓ 7 - ο The next step could be a ‘beta-beam’ in which radioactive nuclei such as He Li e e and

18 19 + Ne ↓ F e οe could be stored and produce low energy beams of pure electron neutrinos or anti-neutrinos. Finally the SPL would also be adequate as proton driver for a muon based Neutrino Factory, which is recognized as the ultimate tool for the study of neutrino oscillations as well as a first stepping-stone towards muon colliders. University of Geneva has largely contributed to the definition of this future neutrino program by the original calculations of the superbeam neutrino flux9, of the performance of a large water Cherenkov detector in this beam and in the beta-beam10, as well as for the evaluation of the capabilities of neutrino factories11, in particular for what concerns the precision in the determination of the neutrino flux12 or the possibility to use both signs of muons13. This has led to many invited conferences14.

This activity has led to the publication of a CERN yellow report15, where University of Geneva contributed to many articles. Mario Campanelli edited the physics section, and Alain Blondel ensured the overall supervision. We also contributed to the equivalent studies in the US16.

Following an encouraging prospective study in 199817 a Neutrino Factory Working Group was created in 1999 by the CERN management. The neutrino factory was stated as one of the 39 possible options for the future of CERN and the R&D for high intensity proton sources and neutrino factories explicitly described in the medium term plan of May 200118. This program made significant contributions leading to a CERN-baseline design for a Neutrino Factory19.

In 2003, ECFA recommended the creation of a European network of Accelerator R&D, which was approved under the FP6 program Integrated Infrastructures under the acronym of CARE. (Coordinated Accelerator Research in Europe). University of Geneva is the university node for Switzerland, which also encompasses University of Bern, Neuchatel, and Zurich. The main activity in which we are involved is the definition of future neutrino beams and experiments for Europe, (BENE20). Edda Gschwendtner was deputy coordinator of BENE until April 2005.

Under sponsorship of ECFA and BENE we organized a workshop on the possible use of a Multi Megawatt proton driver at CERN 25-27 May 2004, the proceedings of which we edited21 and submitted to the CERN SPS committee, for his meeting of 22-28 September in Villars, where in particular the physics case for the Neutrino Factory was presented22. The committee recommended that ‘CERN should support the European Neutrino Factory initiative in its conceptual design’; this statement was endorsed by the CERN Scientific Policy Committee.

Following these encouragements, it is now important to prepare a powerful bid for a Design Study proposal under the European Commission’s Framework Plan 7 (FP7). This preparation is the main aim of the International Scoping Study for a future precision neutrino facility. (ISS)23. The study was launched at the occasion of the NUFACT0524 workshop, in which A. Blondel gave the physics summary talk25. A. Blondel is responsible for the study of detectors for future precision neutrino oscillation experiments. We organized a successful workshop at CERN 22-24 september 2005. Some important results have already been obtained: 1. the preliminary study of the feasibility of a megaton water Cherenkov detector has been presented. It appears that such a detector would be feasible, by combining 5 200 kton caverns. The cost is being evaluated. 2. It appears that a much improved detector design for the neutrino factory could be feasible using the NOVA liquid scintillator approach interspaced with magnetized iron plates, leading to a good acceptance down to a muon momentum of 1.5 GeV/c instead of the previously achieved 4 GeV/c. The consequences of this improvement will now be studied.

5 International Muon Ionization cooling experiment (MICE)

Cooling is an important component of a Neutrino Factory, both in performance and cost. The group is participant in the International Muon Cooling Experiment, the success of which is a crucial milestone in the demonstration of feasibility of a neutrino factory. Alain Blondel initiated the concept of the experiment26, and was elected in 2004 spokesperson of the collaboration.

The basic aims of the experiment27 and a baseline scenario were defined and a letter of Intent submitted to the Paul Scherrer Institute (PSI) and to the Rutherford Appleton Laboratory. A total of 140 authors and 40 institutes, including several teams from large laboratories around the world (Fermilab, CERN, Brookhaven, Berkeley, Legnaro and RAL) are participating in 40 this effort. The directors of RAL and PSI agreed to collaborate on this experiment, PSI providing a beam solenoid to allow RAL to provide a high quality muon beam for the experiment. CERN and LBNL (Berkeley) have agreed to earmark RF equipment for the experiment, some of which has already arrived at RAL. MICE has achieved a high international profile: most conferences and workshops on future neutrino beams28 or accelerator research and development have invited us to present papers.

Figure 19 layout of MICE, the International muon ionization cooling experiment.

Figure 20 The proposed steps in the implementation of MICE. Already step II should lead to publishable results.

Following the encouraging review by a panel of experts from PPARC and CCLRC (RAL)29, a proposal30 was submitted 10 January 2003. The International Review Panel strongly recommended the experiment31, which was formally approved in October 2003 by the CEO of RAL32. A formal (‘Gateway 1’) review was passed in March 2004. The search for funding and or equipment around the world is now progressing. Equipment and funding 41 corresponding to more than 50% of the whole program of MICE has been secured. Resources are sufficient to go ahead with the first steps (see Figure 20); the ‘Gateway 2/3’ review in December 2004 was successful and led to the authorization of construction of the beam line and of the equipment for the first two steps33. Thee experiment is now very active to be ready to take first beams in spring 2007. The final encouragement came from the approval of the proposal by the INFN group to contribute the TOF and the calorimeter, and from the possible collaboration of the Sofia group, thanks to a Swiss SNF SCOPES JRP grant.

5.1 simulation of RF dark current emission

R. Sandström is responsible for the simulations of the emission of electrons (dark currents) and photons from the RF cavities and of their effect on the tracking system. The understanding of field emission by RF cavities submitted to magnetic fields is one of the limiting factors to muon cooling, which requires high gradients to be efficient. At high gradient the field emission (electrons accelerated by the electric field) raises very fast, and the absorption of dark current electrons by the liquid hydrogen absorbers could cause excessive heating. R. Sandström has built a generator of dark current electrons (see Figure 21). This simulation is now a widely used tool for simulations of the trackers. It should soon be tested at Fermilab against measurements on a prototype cavity that is under construction by our collaborators at Berkeley34.

Figure 21 Top: simulation of electrons (red) and photons (green) from dark current electrons in MICE (R. Sandström, O. Voloshyn).35 Middle main process leading to background in the detectors; bottom: the first MICE RF cavity prototype at Jefferson Lab. 42

5.2 Development of a TPC with GEM readout

The trackers have to determine the emittance of the incoming and outgoing beam with a precision of 10-3. As a continuation of our activity in the HARP experiment, we have participated in the development of a helium-filled TPC with GEM readout. We built a prototype GEM readout chamber in collaboration with Legnaro (U. Gastaldi), Bari (E. Radicioni) Napoli (G. Seracino) and CERN (F. Sauli ). The TPG is a cylindrical TPC equipped with GEM amplification and a special high-resolution pad-plane. The novelty of the TPG consists in the pad-plane, where projective readout promises high granularity with a reduced number of channels.

The first full scale readout system of the TPG (including three layers of GEMs and the readout board) has been finished in Spring 200436. Our responsibility has been the design, construction and testing of the hexaboard readout plane with help from the CERN workshops (see Figure 22). The construction and verification of the first full working hexaboard has been completed in spring 2004 and the prototype was tested in the HARP solenoid.

Figure 22: Detail of the hexaboard where the hexagons and underlying connecting strips are clearly visible in transparence through the kapton foil. Right: Sketch of the hexaboard with one third of the pads (blue) connected in strips at 90o, one third at 210o and one third at 330 o. Beautiful tracks of particles parallel to the field lines have been observed The intrinsic resolution of the detector obtained with a 3cm drift cell is 40νm37, (Figure 23).

Due to the delay in Italian funding and to the perceived potential difficulty in calibrating the TPC when operated in very high background conditions, the TPG option has been kept as an upgrade possibility, and our group is redirecting its effort towards the trigger and Data Acquisition of the experiment. Jean-Sebastien Graulich, who joined the Geneva group in July 2005, is now responsible for the data acquisition for the TOF and the Calorimeter and has already made substantial contributions, following the initial work of Edda Gschwendtner 38. We are presently building a data acquisition test stand at Geneva University.

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Figure 23 : Left: Three projections of a measured electron track from a Sr-source in the TPG at a field of 0.07 Tesla. The color code gives the charge. Right: The intrinsic resolution of the TPG readout plane is 40 νm. This is obtained by measuring the position of 55Fe X-ray conversion electrons in 2 projections and then cross-checking with the 3rd one.

6 Dissemination and outreach

In addition to the aforementioned activities of dissemination of our results, we take an important part in the communication with the public, with regular organization of visits to CERN, introduction of particle physics activities to college students etc. In particular we were responsible for the organization of the commemoration of the 50th anniversary of the first steps of CERN at the Institut de Physique in Geneva and of 50 years of collaborations with CERN (Figure 24). At this occasion we built a ‘Cosmophone’ and included in the ceremony39 a few pieces of cosmic music created in collaboration with the conservatoire de musique de Genève. An attendance of more than 500 people was estimated.

Figure 24 Invitation card for the celebration of the 50th anniversary of the first steps of CERN at the University of Geneva, 23 October 2004. On the left some VIPs at the Ceremony: left to right and bottom up: Prof. M. Bourquin (former rector and president of CERN council), Prof. P. Spierer (Dean), Prof. O. Fisher (director of Manep), Mr. G. Brianti (Former CERN accelerator physicist at Unige in 1954), Prof. R. Flukiger (solid state physics, president of the section de physique), Prof. A. Clark, (Director DPNC, President of CHIPP), Mr. R. Aymar (Director General of CERN), Mr. C. Beer, conseiller d’Etat de la république et canton de Geneve in charge of DIP), Prof. A. Hurst (rector), J.-P. Ruder (OFES), Pr. et Mme M. Pohl, Mr. P. Muller (Mayor of Geneva)Prof. G. Veneziano (CERN) and Mme. S. Henchoz (Passerelle Science Cité). 44 We have continued with a series of conferences which have been very successful, each conference starting with a short (15 minutes) concert of cosmophone. The agenda of conferences has been as follows: 7 décembre 2004 'Les preuves expérimentales du Big Bang' , Prof. Georges Meylan (Laboratoire d'Astrophysique, EPFL) : De Hubble à WMAP pourquoi les physiciens modernes croient au Big Bang 1er février 2005 'Et rien ne fut plus comme avant', Prof Chris Quigg (Fermi National Accelerator Laboratory, Chicago) :La brisure de symétrie et l'analogie avec l'évolution 15 mars 2005 'Comment fabrique-t-on un Univers ?’ Prof Alain Blondel (Université de Genève) ; Particules et Forces, le petit lego et la boite à outils du constructeur de mondes 3 mai 2005 'Naissance de la Matière‘ Prof. John Ellis (CERN) 14 juin 2005 'Einstein dans l’Univers‘, Prof. Michele Maggiore (Université de Genève) : La gravitation et la relativité générale. La recherche des gravitons 18 octobre 2005 'Des objections d'Einstein aux bits quantique: les propriétés étranges des photons intriqués' Prof. Alain Aspect (Institut d'Optique, Orsay) ; Intrication, inégalités de Bell et information quantique 14 novembre 2005 (Auditoire Piaget) ‘D’autres mondes dans l’Univers ?', Prof. Michel Mayor (Observatoire de Genève) ;La recherche astronomique et les exo-planètes 13 décembre 2005 'Big Bang à Genève', Dr Laurent Chevalier (CEA, Saclay) Les expériences de physique des particules et les manips LHC au CERN 7 mars 2006 'Nanotechnologies et ordinateurs quantiques' Michel Devoret (Yale University)

We are presently involved in ‘Kid’s University’ a event organized in the context of the League of European Reseaarch Universities, LERU40 , and during which 125 10-12 years old pupils from the Geneva county have visited the laboratories of the section de physique, followed classes, built themselves a water operated rocket, and visited ATLAS!

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A. Cervera et al, Object-Oriented KALMAN-filter package for HEP Analysis, IEEE Nuclear Science Symposium, Portland October 2003. IEEE proceedings.

A. Cervera, HARP Status, NBI2003 (Neutrino Beams and Instrumentation) KEK (Tsukuba)(Oct 2003) IEEE proceedings.

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S. Borghi, The HARP TPC, 9th international seminar on Innovative particle and radiation detectors, Nucl. Phys. B (proc. suppl.) 150 (2005) 223

G. Prior, The HARP experiment: first physics results, Nucl. Phys. A752 (2005) 24c.

M. Campanelli, Status and prospective of HARP, Nucl. Phys. B (Proc. Suppl.) 138 (2005) 408.

M. Campanelli and T. Fernandez Carames, First look at particle identification with dE/dx in the TPC, Harp Memo 2002-005 http://harp.web.cern.ch/harp/Classified/Private/Memoranda/memo/memo02/memo02- 005.pdf

S. Borghi et al., ”Clustering algorithm”, HARP-memo-3-012 http://harp.web.cern.ch/harp/Classified/Private/Memoranda/memo/memo03/memo03-012.pdf

A.Cervera-Villanueva et al., NDC reconstruction & matching with other subdetectors. HARP Memo 2003-14 http://harp.web.cern.ch/harp/Classified/Private/Memoranda/memo/memo03/memo03-014.pdf

S. Borghi, Study of Delta pt in the HARP TPC, HARP memo 2003-16 http://harp.web.cern.ch/harp/Classified/Private/Memoranda/memo/memo03/memo03-016.pdf

2 HARP collaboration, Measurement of the production cross-section of positive pions in p-Al collisions at 12.9 GeV/c. to appear in Nucl. Phys. B

3 M. Apollonio, P. Chimenti, S. Borghi, S. Giani, P. Temnikov HARP-MEMO 05-002: Time calibration and evaluation of the drift velocity.

4 S. Borghi and S. Giani, Study of TPC distortions, HARP memo 2004-04.

5 S. Borghi, U. Gastaldi, S. Giani, P. Temnikov, Elastic scattering reactions and performance of the HARP TPC, HARP memo 005-001 (attached)

6 K2K collab. E. Aliu et al, A. Blondel, S.Borghi, A. Cervera, R. Schroeter, Evidence for muon neutrino oscillation in an accelerator based experiment, PRL 94(2005)081802

7 Letter of Intent: Neutrino Oscillation Experiment at JHF http://neutrino.kek.jp/jhfnu/loi/loi.v2.030528.pdf

8 A. Blondel, P. Béné, A. Cervera, D. Ferrere, F. Masciocchi, E. Perrin, R. Schroeter, T2K ND280 Conceptual Design Report T2K internal document (attached to this report)

9 Study of neutrino oscillations with a low energy conventional neutrino superbeam 46

M. Donegà, Tesi di Laurea, Università degli studi di Milano, March 2001, matr. 508510

Study of (Anti-)Neutrino Fluxes from a Horn Neutrino Beam Using 2.2 GeV Protons A.Blondel, M. Donega, S. Gilardoni, Neutrino Factory Note 78 (2001) http://nicewww.cern.ch/~molat/neutrino/nf78.pdf

Superbeam Studies at CERN A. Blondel et al, Nucl. Instr. Meth.503(2003) 173 http://nicewww.cern.ch/~molat/neutrino/nf95.pdf

A new optics for the SPL Superbeam, S. Gilardoni, NOSC http://axpd24.pd.infn.it/nowg/oscillations.html, October 2002.

10 Reconstruction of neutrino energy in a large water Cherenkov detector using lepton information, A. Blondel, M. Campanelli, M. Fechner, Neutrino Factory Note 112 (2002) , http://nicewww.cern.ch/~molat/Neutrino/nf112.pdf

Study of the Reconstruction of Neutrino Oscillation Parameters Using Spectral Information from a Cherenkov Detector, A. Blondel, A. Campanelli, M. Fechner, Neutrino Factory Note 120 (2002), http://nicewww.cern.ch/~molat/neutrino/nf120.pdf

Energy reconstruction in quasi-elastic events unfolding physics and detector effects A.Blondel, M. Campanelli, M. Fechner, Journal of Physics G29, 8 p. 1907 (2003)

Effects of new physics in neutrino oscillations in matter M. Campanelli, Andrea Romanino, hep-ph/0207350 July 2002 http://xxx.lanl.gov/pdf/hep-ph/0207350 Journal of Physics G29, 8 p. 1861 (2003)

11 Neutrino Factory, beam and experiments: summary A. Blondel et al, Nucl. Instrum. Methods Phys. Res., A 451 (2000) 102

Oscillation Physics with a Neutrino Factory, M. Apollonio et al, (incl. Blondel, Campanelli, Donega, Fechner, Gilardoni, Santin de l’Université de Genève) hep-ph/0210192 October 2002 (edit. M. Campanelli)

12 Why we think we can measure the flux to 10-3 at the neutrino factory. A. Blondel, NuFact03 (Columbia, June 2003) http://www.cap.bnl.gov/nufact03/WG1/7june/blondel.ppt

13 A.Blondel Neutrino Factory Scenarios, presentation at the NUFACT04 workshop, http://www-kuno.phys.sci.osaka-u.ac.jp/~nufact04/wg4.html

14 A. Blondel, Precision physics at neutrino factories, invited presentation at PAVI04 on Parity Violation and Hadronic Structure, Grenoble 2004, The European Physical Journal A - Hadrons and Nuclei Publisher: Springer-Verlag GmbH Volume 24, Supplement 2 Date: February 2005 Pages: 183 - 186

A. Blondel, Physics with the neutrino factory, invited talk at Neutrino 2004(June 2004, Paris) to appear in the proceedings. http://neutrino2004.in2p3.fr/slides/thursday/blondel.ppt

A.Blondel, Physics with the Neutrino Factory, invited presentation HIF04 workshop, Isola d’Elba, June 2004. http://www.pi.infn.it/pm/2004/talks/blondel.ppt, published in the proceedings. 47

A.Blondel, physics with a high intensity proton source, HIF04 workshop, Isola d’Elba, June 2004. http://www.pi.infn.it/pm/2004/talks/blondel2.ppt

A. Blondel, Beyond LHC: some possibilities, invited conclusions talk at ‘Physics at LHC’ Vienna, July 2004, http://wwwhephy.oeaw.ac.at/phlhc04/

A. Blondel, Challenges of future neutrino facilities Invited talk at the Vth rencontres du Vietnam Hanoi 2004 http://vietnam.in2p3.fr/2004/trans/blondel.ppt, to appear in the proceedings.

A.Blondel, Future neutrino beams Invited talk at the 2004 Nobel Symposium on neutrino physics http://www.physics.kth.se/nobel2004/talks/A_Blondel-Future_oscillation_experiments.pdf

Invited member of round table panel discussions in NOVE03, HIF04 Elba, NUFACT04, Osaka, Nobel Symposium 2004, BENE04

15 CERN/ECFA Studies of a European Neutrino Factory Complex, A. Blondel et al., eds. CERN-2004-002.- ECFA-04-230 March 2004. http://preprints.cern.ch/cernrep/2004/2004-002/2004-002.html

16 C. Albright et al, Neutrino Factory and Beta Beam Experiments and Development, BNL- 72369-2004, FNAL-TM-2259, LBNL-55478, (A. Blondel) http://www.cap.bnl.gov/mumu/study2a/REPORT/NF-BB-WG.pdf

17 B. Autin, A. Blondel and J. Ellis, Prospective study of muon storage rings at CERN, CERN 99-02 (1999)

18 The Scientific Activities of CERN and Budget Estimates for the Years 20022005 CERN/SPC/793 (May 2001), p. 62-64.

19 B. Autin, A. Blondel, […],The CERN Neutrino Factory Working Group. Status Report and Work Plan NuFact Note 2001-91

Introduction to the Neutrino Factory, S. Gilardoni ECFA Beam Dynamics Newsletter, No. 29,

The Study of a European Neutrino Factory Complex, P.Gruber(ed.) et al. (76 Authors), CERN-PS-2002-008(NF), CERN, 2002.

Status of Neutrino Factory and Development and Future Plans, R.Raja(ed.) et al. PRSTAB 2002.

A European Neutrino Factory Complex, S. Gilardoni, Proceedings of ICHEP 2002.

Updated Results of the Horn Study For the Neutrino Factory S. Gilardoni, G. Gräwer, G. Maire, J-M.Maugain, S .Rangod, F. Völker , proceedings NUFACT03, A. Para ed. (2004)

20 BENE: Beams for European Neutrino Experiments; http://cern.ch/BENE

48

21 Workshop on physics with a Multi MW proton source, A. Blondel et al. eds., CERN- SPSC-2004-024, SPSC-M-722.

22A. Blondel, Neutrino Factory: the physics case, presentation at the SPSC Villars Workshop Sept. 23 2004 http://agenda.cern.ch/askArchive.php?base=agenda&categ=a043551&id=a043551s9t11/transparencies

23 Main ISS web page http://www.hep.ph.ic.ac.uk/iss/

24 7th International Workshop on Neutrino Factories and Superbeams, Laboratori Nazionali di Frascati, Frascati (Rome)June 21 - 26, 2005 http://www.lnf.infn.it/conference/2005/nufact05/

25 A. Blondel: future neutrino facilities, physics studies and open questions. http://www.lnf.infn.it/conference/nufact05/talks/Plenary/Blondel_Plenary.ppt

26 An International Muon Ionization Cooling Experiment, Goals and preliminary design, A. Blondel, http://hep04.phys.iit.edu/cooldemo/intcoolex.pdf

27 An International Muon Ionization Experiment (MICE), Letter of Intent to the Paul Scherrer Institute (Nov 28) and to The Rutherford Appleton Laboratory A. Blondel et al. (the MICE collaboration) http://hep04.phys.iit.edu/cooldemo/micenotes/public/pdf/MICE0001/MICE0001.pdf

28 A. Blondel, the MICE experiment, invited presentation to the 2d Neutrino Oscillation Workshop in Venice, http://axpd24.pd.infn.it/NO-VE2003/NO-VE.html

29 Report of the joint CLRC/PPARC review Panel, A. Astbury et al., http://hep04.phys.iit.edu/cooldemo/micenotes/public/doc/MICE0002/MICE0002.doc

30 An International Muon Ionization Cooling Experiment (MICE) Proposal to the Rutherford Appleton Laboratory, http://hep04.phys.iit.edu/cooldemo/micenotes/public/pdf/MICE0021/MICE0021.pdf

31 Report from the MICE International Review Panel A. Astbury et al., MICE-Note 34 (May 2003) http://www.mice.iit.edu/micenotes/public/doc/MICE0034/MICE0034.doc

32 MICE Approval Letter, John Wood, (RAL CEO) MICE Note 53 (October 2003) http://www.mice.iit.edu/micenotes/public/pdf/MICE0053/MICE0053.pdf

33 MICE project gets the green light (CERN Courier, May 05) http://www.cerncourier.com/main/article/45/4/1

34 J. Norem, R. Sandstrom, A. Bross A. Moretti, Z. Qian, Y. Torun, R. Rimmer, D. Li, M. Zisman, R. Johnson, the RF development programme at the fermilab MTA, http://mice.iit.edu/micenotes/public/pdf/MICE0098/MICE0098.pdf

35 R. Sandström, Simulation of RF induced background in the MICE experiment, NUFACT04 Nucl. Phys. B (Proc. Suppl.) 149 (2005) 301.

36 V. Ableev et al., TPG construction, Submitted to NIM A 535, Vienna Conference on Instrumentation, VCI, 16-21 February 2004, Vienna, Austria. (E. Gschwendtner, P.Bene, J.-P. Richeux, A. Blondel, G. Prior)

49

37 P. Chimenti et al., TPG Test results, IEEE proceedings, 16-21 October 2004, Rome, Italy. (E. Gschwendtner, P.Bene, J.-P. Richeux, A.Blondel, G. Prior)

38 E. Gschwendtner et al, Data Acquisition Terminology for the Muon Ionization Cooling Experiment MICE http://mice.iit.edu/micenotes/public/pdf/MICE0097/MICE0097.pdf

39 A. Blondel, C. Blanchard et al, http://www.unige.ch/sciences/physique/cern50.html See in particular the article on the cosmophone written by M. Campanelli, A. Blondel and E.Ellberger from the conservatoire de musique de Genève. http://www.unige.ch/sciences/physique/CERN50_cosmophone.html

40 http://www.unige.ch/presse/leru-kids/2005/