W. C. Turner

Measurement of zero degree single photon energy spectra for s=7 TeV proton–proton collisions at LHC

Abstract 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 .

Measurement of forward neutral pion transverse momentum spectra for √s=7TeV proton-proton collisions at the LHC

The inclusive production rate of neutral pions in the rapidity range greater than

Measurement of zero degree inclusive photon energy spectra for s=900GeV proton–proton collisions at LHC

y=8.9

Transverse-momentum distribution and nuclear modification factor for neutral pions in the forward-rapidity region in proton-lead collisions at s NN =5.02 TeV

has been measured by the Large Hadron Collider forward (LHCf) experiment during LHC

Development of a detector for bunch by bunch measurement and optimization of luminosity in the LHC

\sqrt{s}=7

The performance of the LHCf detector for hadronic showers

\,TeV proton-proton collision operation in early 2010. This paper presents the transverse momentum spectra of the neutral pions. The spectra from two independent LHCf detectors are consistent with each other and serve as a cross check of the data. The transverse momentum spectra are also compared with the predictions of several hadronic interaction models that are often used for high energy particle physics and for modeling ultra-high-energy cosmic-ray showers.

Luminosity determination in √s = 7 TeV proton collisions using the LHCf Front Counter at LHC

Abstract The inclusive photon energy spectra measured by the Large Hadron Collider forward (LHCf) experiment in the very forward region of LHC proton–proton collisions at s = 900 GeV are reported. The results from the analysis of 0.30 nb−1 of data collected in May 2010 in the two pseudorapidity regions of η > 10.15 and 8.77 η 9.46 are compared with the predictions of the hadronic interaction models DPMJET 3.04, EPOS 1.99, PYTHIA 8.145, QGSJET II-03 and SIBYLL 2.1, which are widely used in ultra-high energy cosmic ray experiments. EPOS 1.99 and SIBYLL 2.1 show a reasonable agreement with the spectral shape of the experimental data, whereas they predict lower cross-sections than the data. The other models, DPMJET 3.04, QGSJET II-03 and PYTHIA 8.145, are in good agreement with the data below 300 GeV but predict harder energy spectra than the data above 300 GeV. The results of these comparisons exhibited features similar to those for the previously reported data for s = 7 TeV collisions.

An ionization chamber shower detector for the LHC luminosity monitor

The transverse momentum (

Collision rate monitors for LHC

p_\text{T}

LHCf Detector Performance during the 2009-2010 LHC RUN

) distribution for inclusive neutral pions in the very forward rapidity region has been measured, with the Large Hadron Collider forward detector (LHCf), in proton--lead collisions at nucleon-nucleon center-of-mass energies of