A. Kayis-Topaksu

Measurement of charm production in neutrino charged-current interactions

The nuclear emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy from 1994 to 1997. In total, about 100 000 charged-current (CC) neutrino interactions with at least one identified muon were located in the emulsion target and fully reconstructed, using newly developed automated scanning systems. Charmed particles were searched for by a program recognizing particle decays. The observation of the decay in nuclear emulsion makes it possible to select a sample with very low background and minimal kinematical bias. In all, 2013 CC interactions with a charmed hadron candidate in the final state were selected and confirmed through visual inspection. The charm production rate induced by neutrinos relative to the CC cross-section is measured to be σ(νμN→μ−CX)/σ(CC)=(5.75 ± 0.32(stat)±0.30(syst))%. The charm production cross-section as a function of neutrino energy is also obtained. The results are in good agreement with previous measurements. The charm-quark hadronization produces the following charmed hadrons with relative fractions (in %): fD0=43.7±4.5, fΛc+=19.2±4.2, fD+=25.3±4.2 and fDs+=11.8±4.7.

Large-angle production of charged pions with 3-12.9 GeV/c incident protons on nuclear targets

M.G. Catanesi, E. Radicioni, R. Edgecock, M. Ellis, ∗ F.J.P. Soler, C. Gößling, S. Bunyatov, A. Krasnoperov, B. Popov, † V. Serdiouk, V. Tereschenko, E. Di Capua, G. Vidal–Sitjes, ‡ A. Artamonov, § S. Giani, S. Gilardoni, P. Gorbunov, § A. Grant, A. Grossheim, ¶ A. Ivanchenko, ∗∗ V. Ivanchenko, †† A. Kayis-Topaksu, ‡‡ J. Panman, I. Papadopoulos, E. Tcherniaev, I. Tsukerman, § R. Veenhof, C. Wiebusch, §§ P. Zucchelli, ¶¶ A. Blondel, S. Borghi, M.C. Morone, ∗∗∗ G. Prior, † † † R. Schroeter, C. Meurer, U. Gastaldi, G. B. Mills, ‡ ‡ ‡ J.S. Graulich, §§§ G. Grégoire, M. Bonesini, ¶¶¶ F. Ferri, M. Kirsanov, A. Bagulya, V. Grichine, N. Polukhina, V. Palladino, L. Coney, ‡ ‡ ‡ D. Schmitz, ‡ ‡ ‡ G. Barr, A. De Santo, F. Bobisut, D. Gibin, A. Guglielmi, M. Mezzetto, J. Dumarchez, U. Dore, D. Orestano, F. Pastore, A. Tonazzo, L. Tortora, C. Booth, L. Howlett, G. Skoro, M. Bogomilov, M. Chizhov, D. Kolev, R. Tsenov, S. Piperov, P. Temnikov, M. Apollonio, P. Chimenti, G. Giannini, J. Burguet–Castell, A. Cervera–Villanueva, J.J. Gómez–Cadenas, J. Mart́ın–Albo, P. Novella, M. Sorel, and A. Tornero (HARP Collaboration)

Leading order analysis of neutrino induced dimuon events in the CHORUS experiment

We present a leading order QCD analysis of a sample of neutrino induced chargedcurrent events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. The analysis yields a value of the charm quark mass of mc = (1.26 ± 0.16 ± 0.09) GeV/c and a value of the ratio of the strange to non-strange sea in the nucleon of κ = 0.33±0.05±0.05, improving the results obtained in similar analyses by previous experiments.

Measurement of the production cross-sections of pi(+/-) in p-C and pi(+/-)-C interactions at 12 GeV/c

The results of the measurements of the double-differential production cross-sections of pions, dσ/dpdΩ, in p-C and π-C interactions using the forward spectrometer of the HARP experiment are presented. The incident particles are 12 GeV/c protons and charged pions directed onto a carbon target with a thickness of 5% of a nuclear interaction length. For p-C interactions the analysis is performed using 100 035 reconstructed secondary tracks, while the corresponding numbers of tracks for π-C and π-C analyses are 106 534 and 10 122 respectively. Cross-section results are presented in the kinematic range 0.5 GeV/c ≤ pπ < 8 GeV/c and 30 mrad ≤ θπ < 240 mrad in the laboratory frame. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range. HARP collaboration M.G. Catanesi, E. Radicioni Università degli Studi e Sezione INFN, Bari, Italy R. Edgecock, M. Ellis, S. Robbins, F.J.P. Soler Rutherford Appleton Laboratory, Chilton, Didcot, UK C. Gößling Institut für Physik, Universität Dortmund, Germany S. Bunyatov, A. Krasnoperov, B. Popov, V. Tereshchenko Joint Institute for Nuclear Research, JINR Dubna, Russia E. Di Capua, G. Vidal–Sitjes Università degli Studi e Sezione INFN, Ferrara, Italy A. Artamonov, S. Giani, S. Gilardoni, P. Gorbunov, A. Grant, A. Grossheim, P. Gruber, V. Ivanchenko, A. Kayis-Topaksu, J. Panman, I. Papadopoulos, E. Tcherniaev, I. Tsukerman, R. Veenhof, C. Wiebusch, P. Zucchelli CERN, Geneva, Switzerland A. Blondel, S. Borghi, M. Campanelli, M.C. Morone, G. Prior, R. Schroeter Section de Physique, Université de Genève, Switzerland R. Engel, C. Meurer Forschungszentrum Karlsruhe, Institut für Kernphysik, Karlsruhe, Germany I. Kato University of Kyoto, Japan U. Gastaldi Laboratori Nazionali di Legnaro dell’ INFN, Legnaro, Italy G. B. Mills Los Alamos National Laboratory, Los Alamos, USA J.S. Graulich, G. Grégoire Institut de Physique Nucléaire, UCL, Louvain-la-Neuve, Belgium M. Bonesini, F. Ferri Università degli Studi e Sezione INFN, Milano, Italy M. Kirsanov Institute for Nuclear Research, Moscow, Russia A. Bagulya, V. Grichine, N. Polukhina P. N. Lebedev Institute of Physics (FIAN), Russian Academy of Sciences, Moscow, Russia V. Palladino Università “Federico II” e Sezione INFN, Napoli, Italy L. Coney, D. Schmitz Columbia University, New York, USA G. Barr, A. De Santo, C. Pattison, K. Zuber Nuclear and Astrophysics Laboratory, University of Oxford, UK F. Bobisut, D. Gibin, A. Guglielmi, M. Mezzetto Università degli Studi e Sezione INFN, Padova, Italy J. Dumarchez, F. Vannucci LPNHE, Universités de Paris VI et VII, Paris, France U. Dore Università “La Sapienza” e Sezione INFN Roma I, Roma, Italy D. Orestano, F. Pastore, A. Tonazzo, L. Tortora Università degli Studi e Sezione INFN Roma III, Roma, Italy C. Booth, L. Howlett Dept. of Physics, University of Sheffield, UK M. Bogomilov, M. Chizhov, D. Kolev, R. Tsenov Faculty of Physics, St. Kliment Ohridski University, Sofia, Bulgaria S. Piperov, P. Temnikov Institute for Nuclear Research and Nuclear Energy, Academy of Sciences, Sofia, Bulgaria M. Apollonio, P. Chimenti, G. Giannini, G. Santin Università degli Studi e Sezione INFN, Trieste, Italy J. Burguet–Castell, A. Cervera–Villanueva, J.J. Gómez–Cadenas, J. Mart́ın–Albo, P. Novella, M. Sorel Instituto de F́ısica Corpuscular, IFIC, CSIC and Universidad de Valencia, Spain Now at FNAL, Batavia, Illinois, USA. Jointly appointed by Nuclear and Astrophysics Laboratory, University of Oxford, UK. Now at Codian Ltd., Langley, Slough, UK. Now at University of Glasgow, UK. Also supported by LPNHE, Universités de Paris VI et VII, Paris, France. Now at Imperial College, University of London, UK. ITEP, Moscow, Russian Federation. Permanently at Instituto de F́ısica de Cantabria, Univ. de Cantabria, Santander, Spain. Now at SpinX Technologies, Geneva, Switzerland. Now at TRIUMF, Vancouver, Canada. Now at University of St. Gallen, Switzerland. On leave of absence from Ecoanalitica, Moscow State University, Moscow, Russia. Now at Çukurova University, Adana, Turkey. Now at III Phys. Inst. B, RWTH Aachen, Aachen, Germany. On leave of absence from INFN, Sezione di Ferrara, Italy. Now at CERN, Geneva, Switzerland. Now at Univerity of Rome Tor Vergata, Italy. Now at Lawrence Berkeley National Laboratory, Berkeley, California, USA. K2K Collaboration. MiniBooNE Collaboration. Now at Section de Physique, Université de Genève, Switzerland, Switzerland. Now at Royal Holloway, University of London, UK. Now at University of Sussex, Brighton, UK. Now at ESA/ESTEC, Noordwijk, The Netherlands.

Large-angle production of charged pions with incident pion beams on nuclear targets

We gratefully acknowledge the help and support of the PS beam staff and of the numerous technical collaborators who contributed to the detector design, construction, commissioning and operation. In particular, we would like to thank G. Barichello, R. Brocard, K. Burin, V. Carassiti, F. Chignoli, D. Conventi, G. Decreuse, M. Delattre, C. Detraz, A. Domeniconi, M. Dwuznik, F. Evangelisti, B. Friend, A. Iaciofano, I. Krasin, D. Lacroix, J.-C. Legrand, M. Lobello, M. Lollo, J. Loquet, F. Marinilli, J. Mulon, L. Musa, R. Nicholson, A. Pepato, P. Petev, X. Pons, I. Rusinov, M. Scandurra, E. Usenko, and R. van der Vlugt, for their support in the construction of the detector. The collaboration acknowledges the major contributions and advice of M. Baldo-Ceolin, L. Linssen, M.T. Muciaccia and A. Pullia during the construction of the experiment. The collaboration is indebted to V. Ableev, P. Arce, F. Bergsma, P. Binko, E. Boter, C. Buttar, M. Calvi, M. Campanelli, C. Cavion, A. Chukanov, A. De Min, M. Doucet, D. Dullmann, R. Engel, V. Ermilova, W. Flegel, P. Gruber, Y. Hayato, P. Hodgson, A. Ichikawa, I. Kato, O. Klimov, T. Kobayashi, D. Kustov, M. Laveder, M. Mass, H. Meinhard, T. Nakaya, K. Nishikawa, M. Paganoni, F. Paleari, M. Pasquali, J. Pasternak, C. Pattison, M. Placentino, S. Robbins, G. Santin, V. Serdiouk, S. Simone, A. Tornero, S. Troquereau, S. Ueda, A. Valassi, F. Vannucci and K. Zuber for their contributions to the experiment and to P. Dini for help in MC production. We acknowledge the contributions of V. Ammosov, G. Chelkov, D. Dedovich, F. Dydak, M. Gostkin, A. Guskov, D. Khartchenko, V. Koreshev, Z. Kroumchtein, I. Nefedov, A. Semak, J. Wotschack, V. Zaets and A. Zhemchugov to the work described in this paper. The experiment was made possible by grants from the Institut Interuniversitaire des Sciences Nucleaires and the Interuniversitair Instituut voor Kernwetenschappen (Belgium), Ministerio de Educacion y Ciencia, Grant FPA2003-06921-c02-02 and Generalitat Valenciana, grant GV00-054-1, CERN (Geneva, Switzerland), the German Bundesministerium fur Bildung und Forschung (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), INR RAS (Moscow), the Russian Foundation for Basic Research (grant 08-02-00018) and the Particle Physics and Astronomy Research Council (UK). We gratefully acknowledge their support. This work was supported in part by the Swiss National Science Foundation and the Swiss Agency for Development and Cooperation in the framework of the programme SCOPES - Scientific co-operation between Eastern Europe and Switzerland.

Forward production of charged pions with incident protons on nuclear targets at the CERN Proton Synchrotron

Measurements of the double-differential π production cross-section in the range of momentum 0.5 GeV/c ≤ p ≤ 8.0 GeV/c and angle 0.025 rad ≤ θ ≤ 0.25 rad in collisions of protons on beryllium, carbon, nitrogen, oxygen, aluminium, copper, tin, tantalum and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. Incident particles were identified by an elaborate system of beam detectors. Thin targets of 5% of a nuclear interaction length were used. The tracking and identification of the produced particles were performed using the forward system of the HARP experiment. Results are obtained for the double-differential cross-sections dσ/dpdΩ mainly at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). Measurements are compared with the GEANT4 and MARS Monte Carlo generators. A global parametrization is provided as an approximation of all the collected datasets which can serve as a tool for quick yields estimates.

Absolute momentum calibration of the HARP TPC

In the HARP experiment the large-angle spectrometer is using a cylindrical TPC as main tracking and particle identification detector. The momentum scale of reconstructed tracks in the TPC is the most important systematic error for the majority of kinematic bins used for the HARP measurements of the double-differential production cross-section of charged pions in proton interactions on nuclear targets at large angle. The HARP TPC operated with a number of hardware shortfalls and operational mistakes. Thus it was important to control and characterize its momentum calibration. While it was not possible to enter a direct particle beam into the sensitive volume of the TPC to calibrate the detector, a set of physical processes and detector properties were exploited to achieve a precise calibration of the apparatus. In the following we recall the main issues concerning the momentum measurement in the HARP TPC, and describe the crosschecks made to validate the momentum scale. As a conclusion, this analysis demonstrates that the measurement of momentum is correct within the published precision of 3%.

Observation of one event with the characteristics of associated charm production in neutrino charged-current interactions

Abstract We report on a search for associated charm production in neutrino charged-current interactions in the CHORUS experiment, based on the visual observation of charmed-particle decays. The search differs from those carried out so far in which the production of c c has been inferred from measurements of events with two or three muons in the final state, resulting from the decay of charmed hadrons. One event with a double charm-decay topology has been found and a corresponding background of 0.04 events has been evaluated.

Forward production of charged pions with incident pi(+/-) on nuclear targets measured at the CERN PS

Measurements of the double-differential π production cross-section in the range of momentum 0.5 GeV/c ≤ p ≤ 8.0 GeV/c and angle 0.025 rad ≤ θ ≤ 0.25 rad in interactions of charged pions on beryllium, carbon, aluminium, copper, tin, tantalum and lead are presented. These data represent the first experimental campaign to systematically measure forward pion hadroproduction. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. Incident particles, impinging on a 5% nuclear interaction length target, were identified by an elaborate system of beam detectors. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP detector. Results are obtained for the doubledifferential cross-sections dσ/dpdΩ mainly at four incident pion beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). The measurements are compared with the GEANT4 and MARS Monte Carlo simulation.

Forward pi+/- production in p-O(2) and p-N(2) interactions at 12-GeV/c

Measurements of double-differential charged pion production cross-sections in interactions of 12 GeV/c protons on O2 and N2 thin targets are presented in the kinematic range 0.5 GeV/c ≤ pπ < 8 GeV/c and 50 mrad ≤ θπ < 250 mrad (in the laboratory frame) and are compared with p–C results. For p–N2 (p– O2) interactions the analysis is performed using 38576 (7522) reconstructed secondary pions. The analysis uses the beam instrumentation and the forward spectrometer of the HARP experiment at CERN PS. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range. In particular, the present results allow the common hypothesis that p–C data can be used to predict the p–N2 and p–O2 pion production cross-sections to be tested. Submitted to Astroparticle Physics M.G. Catanesi, E. Radicioni Sezione INFN, Bari, Italy R. Edgecock, M. Ellis Rutherford Appleton Laboratory, Chilton, Didcot, UK C. Gößling Institut für Physik, Universität Dortmund, Germany S. Bunyatov, A. Krasnoperov, B. Popov, V. Tereschenko Joint Institute for Nuclear Research, JINR Dubna, Russia E. Di Capua, G. Vidal–Sitjes Università degli Studi e Sezione INFN, Ferrara, Italy A. Artamonov, S. Giani, S. Gilardoni, P. Gorbunov, A. Grant, A. Grossheim, A. Ivanchenko, V. Ivanchenko, A. Kayis-Topaksu, J. Panman, I. Papadopoulos, E. Tcherniaev, I. Tsukerman, C. Wiebusch, P. Zucchelli CERN, Geneva, Switzerland A. Blondel, S. Borghi, M.C. Morone, G. Prior, R. Schroeter Section de Physique, Université de Genève, Switzerland C. Meurer Institut für Physik, Forschungszentrum Karlsruhe, Germany U. Gastaldi Laboratori Nazionali di Legnaro dell’ INFN, Legnaro, Italy G. B. Mills Los Alamos National Laboratory, Los Alamos, USA J.S. Graulich, G. Grégoire Institut de Physique Nucléaire, UCL, Louvain-la-Neuve, Belgium M. Bonesini, F. Ferri Sezione INFN Milano Bicocca, Milano, Italy