TY - JOUR
T1 - Measurement of zero degree single photon energy spectra for √s=7 TeV proton-proton collisions at LHC
AU - Adriani, O.
AU - Bonechi, L.
AU - Bongi, M.
AU - Castellini, G.
AU - D'Alessandro, R.
AU - Faus, A.
AU - Fukatsu, K.
AU - Haguenauer, M.
AU - Itow, Y.
AU - Kasahara, K.
AU - Kawade, K.
AU - Macina, D.
AU - Mase, T.
AU - Masuda, K.
AU - Matsubara, Y.
AU - Menjo, H.
AU - Mitsuka, G.
AU - Muraki, Y.
AU - Nakai, M.
AU - Noda, K.
AU - Papini, P.
AU - Perrot, A. L.
AU - Ricciarini, S.
AU - Sako, T.
AU - Shimizu, Y.
AU - Suzuki, K.
AU - Suzuki, T.
AU - Taki, K.
AU - Tamura, T.
AU - Torii, S.
AU - Tricomi, A.
AU - Turner, W. C.
AU - Velasco, J.
AU - Viciani, A.
AU - Yoshida, K.
N1 - Funding Information:
We thank the CERN staff and the ATLAS Collaboration for their essential contributions to the successful operation of LHCf. Especially we appreciate continuous review of the experiment by Michelangelo Mangano, Carsten Niebuhr and Mario Calvetti. We also thank Tanguy Pierog for a quick verification of our MC calculations. This work is partly supported by Grant-in-Aid for Scientific Research by MEXT of Japan , the Mitsubishi Foundation in Japan and INFN in Italy . The receipts of JSPS Research Fellowship (H.M. and T.M.), INFN fellowship for non-Italian citizens (H.M. and K.N.) and the GCOE Program of Nagoya University “QFPU” from JSPS and MEXT of Japan (G.M.) are also acknowledged. A part of this work was performed using the computer resource provided by the Institute for the Cosmic-Ray Research (ICRR), University of Tokyo.
PY - 2011/9/7
Y1 - 2011/9/7
N2 - In early 2010, the Large Hadron Collider forward (LHCf) experiment measured very forward neutral particle spectra in LHC proton-proton collisions. From a limited data set taken under the best beam conditions (low beam-gas background and low occurrence of pile-up events), the single photon spectra at √s=7 TeV and pseudo-rapidity (Η) ranges from 8.81 to 8.99 and from 10.94 to infinity were obtained for the first time and are reported in this Letter. The spectra from two independent LHCf detectors are consistent with one another and serve as a cross check of the data. The photon spectra are also compared with the predictions of several hadron interaction models that are used extensively for modeling ultra-high energy cosmic-ray showers. Despite conservative estimates for the systematic errors, none of the models agree perfectly with the measurements. A notable difference is found between the data and the DPMJET 3.04 and PYTHIA 8.145 hadron interaction models above 2 TeV where the models predict higher photon yield than the data. The QGSJET II-03 model predicts overall lower photon yield than the data, especially above 2 TeV in the rapidity range 8.81<η<8.99.
AB - In early 2010, the Large Hadron Collider forward (LHCf) experiment measured very forward neutral particle spectra in LHC proton-proton collisions. From a limited data set taken under the best beam conditions (low beam-gas background and low occurrence of pile-up events), the single photon spectra at √s=7 TeV and pseudo-rapidity (Η) ranges from 8.81 to 8.99 and from 10.94 to infinity were obtained for the first time and are reported in this Letter. The spectra from two independent LHCf detectors are consistent with one another and serve as a cross check of the data. The photon spectra are also compared with the predictions of several hadron interaction models that are used extensively for modeling ultra-high energy cosmic-ray showers. Despite conservative estimates for the systematic errors, none of the models agree perfectly with the measurements. A notable difference is found between the data and the DPMJET 3.04 and PYTHIA 8.145 hadron interaction models above 2 TeV where the models predict higher photon yield than the data. The QGSJET II-03 model predicts overall lower photon yield than the data, especially above 2 TeV in the rapidity range 8.81<η<8.99.
KW - Hadron interaction models
KW - LHC
KW - Ultra-high energy cosmic-ray
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U2 - 10.1016/j.physletb.2011.07.077
DO - 10.1016/j.physletb.2011.07.077
M3 - Article
AN - SCOPUS:80051875955
SN - 0370-2693
VL - 703
SP - 128
EP - 134
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 2
ER -