Measurement of very forward neutron energy spectra for 7 TeV proton--proton collisions at the Large Hadron Collider

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
Phys.Lett.B 750 (2015) 360-366, 2015.
Inspire Record 1351909 DOI 10.17182/hepdata.73320

The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC $\sqrt{s}$ = 7 TeV proton--proton collisions with the pseudo-rapidity $\eta$ ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the difference in the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results and the DPMJET 3.04 model describes our results well at the lower pseudo-rapidity ranges. However no model perfectly explains the experimental results in the whole pseudo-rapidity range. The experimental data indicate the most abundant neutron production rate relative to the photon production, which does not agree with predictions of the models.

1 data table match query

Differential neutron production rate d$\sigma_{n}$/dE [mb/GeV] for each rapidity range.


Measurement of energy flow, cross section and average inelasticity of forward neutrons produced in $\mathrm{\sqrt{s} = 13 TeV}$ proton-proton collisions with the LHCf Arm2 detector

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
JHEP 07 (2020) 016, 2020.
Inspire Record 1783943 DOI 10.17182/hepdata.130268

In this paper, we report the measurement of the energy flow, the cross section and the average inelasticity of forward neutrons (+ antineutrons) produced in $\sqrt{s} = 13$ 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 ($\eta > 10.75$, $8.99 < \eta < 9.21$ and $8.80 < \eta < 8.99$), albeit with smaller acceptance and larger uncertainties, were already published in a previous work, whereas the remaining three ($10.06 < \eta < 10.75$, $9.65 < \eta < 10.06$ and $8.65 < \eta < 8.80$) 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 $\mathrm{0.194~nb^{-1}}$. 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 $\eta > 10.75$ 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.

9 data tables match query

Neutron (and antineutron) inclusive differential production cross section in $\eta > 10.75$

Neutron (and antineutron) inclusive differential production cross section in $10.06 < \eta < 10.75$

Neutron (and antineutron) inclusive differential production cross section in $9.65 < \eta < 10.06$

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Transverse momentum distribution and nuclear modification factor of forward neutral pion in proton--lead collisions at $\sqrt{s_{NN}} = 5.02$TeV

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
Phys.Rev.C 89 (2014) 065209, 2014.
Inspire Record 1287922 DOI 10.17182/hepdata.64158

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.

6 data tables match query

Production rate for PI0 production in the rapidity range -8.9 to -9.0.

Production rate for PI0 production in the rapidity range -9.0 to -9.2.

Production rate for PI0 production in the rapidity range -9.2 to -9.4.

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Measurement of forward photon production cross-section in proton–proton collisions at $\sqrt{s}$ = 13 TeV with the LHCf detector

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
Phys.Lett.B 780 (2018) 233-239, 2018.
Inspire Record 1518782 DOI 10.17182/hepdata.86566

In this paper, we report the production cross-section of forward photons in the pseudorapidity regions of $\eta\,&gt;\,10.94$ and $8.99\,&gt;\,\eta\,&gt;\,8.81$, measured by the LHCf experiment with proton--proton collisions at $\sqrt{s}$ = 13 TeV. The results from the analysis of 0.191 $\mathrm{nb^{-1}}$ of data obtained in June 2015 are compared to the predictions of several hadronic interaction models that are used in air-shower simulations for ultra-high-energy cosmic rays. Although none of the models agree perfectly with the data, EPOS-LHC shows the best agreement with the experimental data among the models.

2 data tables match query

Inclusive photon production cross section in $\eta > 10.94$

Inclusive photon production cross section in $8.81<\eta<8.99$


Measurement of forward neutral pion transverse momentum spectra for $\sqrt{s}$ = 7TeV proton-proton collisions at LHC

The LHCf collaboration Adriani, O. ; Bonechi, L. ; Bongi, M. ; et al.
Phys.Rev.D 86 (2012) 092001, 2012.
Inspire Record 1115479 DOI 10.17182/hepdata.59925

The inclusive production rate of neutral pions in the rapidity range greater than $y=8.9$ has been measured by the Large Hadron Collider forward (LHCf) experiment during LHC $\sqrt{s}=7$\,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.

6 data tables match query

Production rate for PI0 production in the rapidity range 8.9-9.0.

Production rate for PI0 production in the rapidity range 9.0-9.2.

Production rate for PI0 production in the rapidity range 9.2-9.4.

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Measurements of longitudinal and transverse momentum distributions for neutral pions in the forward-rapidity region with the LHCf detector

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
Phys.Rev.D 94 (2016) 032007, 2016.
Inspire Record 1385877 DOI 10.17182/hepdata.74066

The differential cross sections for inclusive neutral pions as a function of transverse and longitudinal momentum in the very forward rapidity region have been measured at the Large Hadron Collider (LHC) with the Large Hadron Collider forward detector (LHCf) in proton-proton collisions at $\sqrt{s}=$ 2.76 and 7 TeV and in proton-lead collisions at nucleon-nucleon center-of-mass energies of $\sqrt{s_\text{NN}}=$ 5.02 TeV. Such differential cross sections in proton-proton collisions are compatible with the hypotheses of limiting fragmentation and Feynman scaling. Comparing proton-proton with proton-lead collisions, we find a sizable suppression of the production of neutral pions in the differential cross sections after subtraction of ultra-peripheral proton-lead collisions. This suppression corresponds to the nuclear modification factor value of about 0.1-0.3. The experimental measurements presented in this paper provide a benchmark for the hadronic interaction Monte Carlo simulation codes that are used for the simulation of cosmic ray air showers.

20 data tables match query

The average $\pi^{0}$ transverse momenta for the rapidity range $8.8<y<10.6$ in $p+p$ collisions at $\sqrt{s}=2.76$ and 7 TeV and for the rapidity range $-8.8>y_\rm{lab}>-10.6$ in $p+\rm{Pb}$ collisions at $\sqrt{s_\rm{NN}}=5.02$ TeV. The rapidity values for $p+\rm{Pb}$ collisions are in the detector reference frame and must be multiplied by -1.

Production rate for the $\pi^{0}$ production in the rapidity range $8.8 < y < 9.0$ in $p+p$ collisions and in the rapidity range $-8.8 > y_\rm{lab} > -9.0$ in $p+\rm{Pb}$ collisions.

Production rate for the $\pi^{0}$ production in the rapidity range $9.0 < y < 9.2$ in $p+p$ collisions and in the rapidity range $-9.0 > y_\rm{lab} > -9.2$ in $p+\rm{Pb}$ collisions.

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Measurement of inclusive forward neutron production cross section in proton-proton collisions at $\mathrm{\sqrt{s} = 13~TeV}$ with the LHCf Arm2 detector

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
JHEP 11 (2018) 073, 2018.
Inspire Record 1692008 DOI 10.17182/hepdata.87099

In this paper, we report the measurement relative to the production of forward neutrons in proton-proton collisions at $\mathrm{\sqrt{s} = 13~TeV}$ 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: $\eta > 10.76$, $8.99 < \eta < 9.22$ and $8.81 < \eta < 8.99$. The analysis was performed using a data set acquired in June 2015 that corresponds to an integrated luminosity of $\mathrm{0.194~nb^{-1}}$. 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 $\eta > 10.76$, no model is able to reproduce the observed peak structure at around $\mathrm{5~TeV}$ 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 $8.99 < \eta < 9.22$ and $8.81 < \eta < 8.99$, 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 $\mathrm{1.5-2.5~TeV}$.

3 data tables match query

Inclusive neutron (and antineutron) production cross section in $\eta > 10.76$

Inclusive neutron (and antineutron) production cross section in $8.99 < \eta < 9.22$

Inclusive neutron (and antineutron) production cross section in $8.81 < \eta < 8.99$


Measurement of the forward-backward asymmetry in the distribution of leptons in $t\bar{t}$ events in the lepton+jets channel

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Rev.D 90 (2014) 072001, 2014.
Inspire Record 1283842 DOI 10.17182/hepdata.64673

We present measurements of the forward-backward asymmetry in the angular distribution of leptons from decays of top quarks and antiquarks produced in proton-antiproton collisions. We consider the final state containing a lepton and at least three jets. The entire sample of data collected by the D0 experiment during Run II of the Fermilab Tevatron Collider, corresponding to 9.7 inverse fb of integrated luminosity, is used. The asymmetry measured for reconstructed leptons is $A_{FB}^l = \big(2.9 \pm 2.1(stat.) ^{+1.5}_{-1.7}(syst.) \big)$%. When corrected for efficiency and resolution effects within the lepton rapidity coverage of $|y_l|<1.5$, the asymmetry is found to be $A_{FB}^l = \big(4.2 \pm 2.3(stat.) ^{+1.7}_{-2.0}(syst.) \big)$%. Combination with the asymmetry measured in the dilepton final state yields $A_{FB}^l = \big(4.2 \pm 2.0(stat.) \pm 1.4(syst.) \big)$%. We examine the dependence of $A_{FB}^l$ on the transverse momentum and rapidity of the lepton. The results are in agreement with predictions from the next-to-leading-order QCD generator \mcatnlo, which predicts an asymmetry of $A_{FB}^l = 2.0$% for $|y_l|<1.5$.

14 data tables match query

Observed ASYMFB(LEPTON) as a function of PT(LEPTON) at reconstruction level.

Observed production-level ASYMFB(LEPTON) as a function of PT(LEPTON).

Observed production-level ASYMFB(LEPTON) as a function of ABS(YRAP(LEPTON)).

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Measurement of the $\phi^*_\eta$ distribution of muon pairs with masses between 30 and 500 GeV in 10.4 fb$^{-1}$ of $p\bar{p}$ collisions

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Rev.D 91 (2015) 072002, 2015.
Inspire Record 1324946 DOI 10.17182/hepdata.72484

We present a measurement of the distribution of the variable $\phi^*_\eta$ for muon pairs with masses between 30 and 500 GeV, using the complete Run II data set collected by the D0 detector at the Fermilab Tevatron proton-antiproton collider. This corresponds to an integrated luminosity of 10.4 fb$^{-1}$ at $\sqrt{s}$ = 1.96 TeV. The data are corrected for detector effects and presented in bins of dimuon rapidity and mass. The variable $\phi^*_\eta$ probes the same physical effects as the $Z/\gamma^*$ boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. These are the first measurements at any collider of the $\phi^*_\eta$ distributions for dilepton masses away from the $Z\rightarrow \ell^+\ell^-$ boson mass peak. The data are compared to QCD predictions based on the resummation of multiple soft gluons.

6 data tables match query

Table of results for the dimuon channel for $|y|<1$ region with $70 < M_{\ell\ell} < 110$ GeV. The first quoted uncertainty is statistical and the second is the total experimental systematic uncertainty.

Table of results for the dimuon channel for $1<|y|<2$ region with $70 < M_{\ell\ell} < 110$ GeV. The first quoted uncertainty is statistical and the second is the total experimental systematic uncertainty.

Table of results for the dimuon channel for $|y|<1$ region $30 < M_{\ell\ell} < 60$ GeV. The first quoted uncertainty is statistical and the second is the total experimental systematic uncertainty.

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Double parton interactions in photon + 3 jet and photon + b/c jet + 2 jet events in ppbar collisions at sqrt{s}=1.96 TeV

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Rev.D 89 (2014) 072006, 2014.
Inspire Record 1280531 DOI 10.17182/hepdata.64745

We determine the fraction of events with double parton (DP) scattering in a single ppbar collision at sqrt{s}=1.96 TeV in samples of photon + 3 jet and photon + b/c jet + 2 jet events collected with the D0 detector and corresponding to an integrated luminosity of about 8.7 fb^{-1}. The DP fractions and effective cross sections (sigma_eff) are measured for both event samples using the same kinematic selections. The measured DP fractions range from 0.21 to 0.17, with effective cross sections in the photon + 3 jet and photon + b/c jet + 2 jet samples of sigma_eff^incl = 12.7 +- 0.2 (stat) +- 1.3 (syst) mb and sigma_eff^HF = 14.6 +- 0.6 (stat) +- 3.2 (syst) mb, respectively.

1 data table match query

The effective cross sections measured for the inclusive and heavy flavour event samples.