A
bstract
In this paper, we report the measurement of the energy flow, the cross section and the average inelasticity of forward neutrons (+ antineutrons) produced in
s
= 13 TeV proton-proton ...collisions. These quantities are obtained from the inclusive differential production cross section, measured using the LHCf Arm2 detector at the CERN Large Hadron Collider. The measurements are performed in six pseudorapidity regions: three of them (
η >
10
.
75, 8
.
99
< η <
9
.
21 and 8
.
80
< η <
8
.
99), albeit with smaller acceptance and larger uncertainties, were already published in a previous work, whereas the remaining three (10
.
06
< η <
10
.
75, 9
.
65
< η <
10
.
06 and 8
.
65
< η <
8
.
80) are presented here for the first time. The analysis was carried out using a data set acquired in June 2015 with a corresponding integrated luminosity of 0
.
194 nb
−
1
. Comparing the experimental measurements with the expectations of several hadronic interaction models used to simulate cosmic ray air showers, none of these generators resulted to have a satisfactory agreement in all the phase space selected for the analysis. The inclusive differential production cross section for
η >
10
.
75 is not reproduced by any model, whereas the results still indicate a significant but less serious deviation at lower pseudorapidities. Depending on the pseudorapidity region, the generators showing the best overall agreement with data are either SIBYLL 2.3 or EPOS-LHC. Furthermore, apart from the most forward region, the derived energy flow and cross section distributions are best reproduced by EPOS-LHC. Finally, even if none of the models describe the elasticity distribution in a satisfactory way, the extracted average inelasticity is consistent with the QGSJET II-04 value, while most of the other generators give values that lie just outside the experimental uncertainties.
A
bstract
In this paper, we report the measurement relative to the production of forward neutrons in proton-proton collisions at
s
=
13
TeV obtained using the LHCf Arm2 detector at the Large Hadron ...Collider. The results for the inclusive differential production cross section are presented as a function of energy in three different pseudorapidity regions:
η
> 10.76, 8.99 <
η
< 9.22 and 8.81 <
η
< 8.99. The analysis was performed using a data set acquired in June 2015 that corresponds to an integrated luminosity of 0.194 nb
−1
. The measurements were compared with the predictions of several hadronic interaction models used to simulate air showers generated by Ultra High Energy Cosmic Rays. None of these generators showed good agreement with the data for all pseudorapidity intervals. For
η
> 10.76, no model is able to reproduce the observed peak structure at around 5 TeV and all models underestimate the total production cross section: among them, QGSJET II-04 shows the smallest deficit with respect to data for the whole energy range. For 8.99 <
η
< 9.22 and 8.81 <
η
< 8.99, the models having the best overall agreement with data are SIBYLL 2.3 and EPOS-LHC, respectively: in particular, in both regions SIBYLL 2.3 is able to reproduce the observed peak structure at around 1.5–2.5 TeV.
A
bstract
The forward
η
mesons production has been observed by the Large Hadron Collider forward (LHCf) experiment in proton-proton collision at
s
= 13 TeV. This paper presents the measurement of the ...inclusive production rate of
η
in
p
T
<
1
.
1 GeV/c, expressed as a function of the Feynman-
x
variable. These results are compared with the predictions of several hadronic interaction models commonly used for the modelling of the air showers produced by ultra-high energy cosmic rays. This is both the first measurement of
η
mesons from LHCf and the first time a particle containing strange quarks has been observed in the forward region for high-energy collisions. These results will provide a powerful constraint on hadronic interaction models for the purpose of improving the understanding of the processes underlying the air showers produced in the Earth’s atmosphere by ultra-energetic cosmic rays.
A
bstract
The forward
η
mesons production has been observed by the Large Hadron Collider forward (LHCf) experiment in proton-proton collision at
$$ \sqrt{s} $$
s
= 13 TeV. This paper presents the ...measurement of the inclusive production rate of
η
in
p
T
<
1
.
1 GeV/c, expressed as a function of the Feynman-
x
variable. These results are compared with the predictions of several hadronic interaction models commonly used for the modelling of the air showers produced by ultra-high energy cosmic rays. This is both the first measurement of
η
mesons from LHCf and the first time a particle containing strange quarks has been observed in the forward region for high-energy collisions. These results will provide a powerful constraint on hadronic interaction models for the purpose of improving the understanding of the processes underlying the air showers produced in the Earth’s atmosphere by ultra-energetic cosmic rays.
The direct detection of high-energy cosmic rays up to the PeV region is one of the major challenges for the next generation of space-borne cosmic-ray detectors. The physics performance will be ...primarily determined by their geometrical acceptance and energy resolution. CaloCube is a homogeneous calorimeter whose geometry allows an almost isotropic response, so as to detect particles arriving from every direction in space, thus maximizing the acceptance. A comparative study of different scintillating materials and mechanical structures has been performed by means of Monte Carlo simulation. The scintillation-Cherenkov dual read-out technique has been also considered and its benefit evaluated.
A
bstract
In this paper, we report the measurement relative to the production of forward neutrons in proton-proton collisions at
$$ \sqrt{s}=13 $$
s
=
13
TeV obtained using the LHCf Arm2 detector at ...the Large Hadron Collider. The results for the inclusive differential production cross section are presented as a function of energy in three different pseudorapidity regions:
η
> 10.76, 8.99 <
η
< 9.22 and 8.81 <
η
< 8.99. The analysis was performed using a data set acquired in June 2015 that corresponds to an integrated luminosity of 0.194 nb
−1
. The measurements were compared with the predictions of several hadronic interaction models used to simulate air showers generated by Ultra High Energy Cosmic Rays. None of these generators showed good agreement with the data for all pseudorapidity intervals. For
η
> 10.76, no model is able to reproduce the observed peak structure at around 5 TeV and all models underestimate the total production cross section: among them, QGSJET II-04 shows the smallest deficit with respect to data for the whole energy range. For 8.99 <
η
< 9.22 and 8.81 <
η
< 8.99, the models having the best overall agreement with data are SIBYLL 2.3 and EPOS-LHC, respectively: in particular, in both regions SIBYLL 2.3 is able to reproduce the observed peak structure at around 1.5–2.5 TeV.
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