Abstract
The transverse momentum ($p_\text{T}$) 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 $\sqrt{s_{NN}} = 5.02$TeV at the LHC. The $p_\text{T}$ spectra obtained in the rapidity range $-11.0 < y_\text{lab} < -8.9$ and $0 < p_\text{T} < 0.6$GeV (in the detector reference frame) show a strong suppression of the production of neutral pions after taking into account ultra-peripheral collisions. This leads to a nuclear modification factor value, relative to the interpolated $p_\text{T}$ spectra in proton-proton collisions at $\sqrt{s} = 5.02$TeV, of about 0.1--0.4. This value is compared with the predictions of several hadronic interaction Monte Carlo simulations.
Highlights
Measurements of particle production in hadronic interactions at high energies play an unique role in the study of strong interactions described by quantum chromodynamics (QCD)
Understanding of particle production in very forward rapidity regions in nuclear target interactions is of importance for ultrahigh-energy cosmic ray interactions, where parton density is due to the expected to dependence be of much higher Bjorken-x ∝
ALHrmC2[w12e,r1e3a]s.sIenmpbl-ePdbocroiglliinsaiollnystoatst√udsyNNp-=p collisions at the 5.02 TeV, only the Large Hadron Collider forward (LHCf) Arm2 detector was used to measure the secondary particles emitted into the proton remnant side
Summary
Measurements of particle production in hadronic interactions at high energies play an unique role in the study of strong interactions described by quantum chromodynamics (QCD). As first discovered in measurements at HERA [1,2], it is still not well understood how a parton (dominantly gluon) density increases or even saturates when the momentum fraction that the parton itself carries is small (denoted as Bjorken-x) This remains true even though the understanding of the behavior of hadron constituents (partons) has been improving both theoretically and experimentally in the past few decades. Understanding of particle production in very forward rapidity regions in nuclear target interactions is of importance for ultrahigh-energy cosmic ray interactions, where parton density is due to the expected to dependence be of much higher Bjorken-x ∝. The LHCf detectors (see Sec. II) cover a pseudorapidity range larger than 8.4 and are capable of precise measurements of the forward high-energy inclusive-particleproduction cross sections of photons, neutrons, and other neutral mesons and baryons.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
