Underlying-event properties in pp and p$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

The ALICE collaboration Acharya, S. ; Adamová, D. ; Adler, A. ; et al.
JHEP 06 (2023) 023, 2023.
Inspire Record 2071174 DOI 10.17182/hepdata.133032

We report about the properties of the underlying event measured with ALICE at the LHC in pp and p$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV. The event activity, quantified by charged-particle number and summed-$p_{\rm T}$ densities, is measured as a function of the leading-particle transverse momentum ($p_{\rm T}^{\rm trig}$). These quantities are studied in three azimuthal-angle regions relative to the leading particle in the event: toward, away, and transverse. Results are presented for three different $p_{\rm T}$ thresholds (0.15, 0.5, and 1 GeV/$c$) at mid-pseudorapidity ($|\eta|<0.8$). The event activity in the transverse region, which is the most sensitive to the underlying event, exhibits similar behaviour in both pp and p$-$Pb collisions, namely, a steep increase with $p_{\rm T}^{\rm trig}$ for low $p_{\rm T}^{\rm trig}$, followed by a saturation at $p_{\rm T}^{\rm trig} \approx 5$ GeV/$c$. The results from pp collisions are compared with existing measurements at other centre-of-mass energies. The quantities in the toward and away regions are also analyzed after the subtraction of the contribution measured in the transverse region. The remaining jet-like particle densities are consistent in pp and p$-$Pb collisions for $p_{\rm T}^{\rm trig}>10$ GeV/$c$, whereas for lower $p_{\rm T}^{\rm trig}$ values the event activity is slightly higher in p$-$Pb than in pp collisions. The measurements are compared with predictions from the PYTHIA 8 and EPOS LHC Monte Carlo event generators.

10 data tables

Fig. 4: Number density $N_{\rm ch}$ (left) and $\Sigma p_{\rm T}$ (right) distributions as a function of $p_{\rm T}^{\rm trig}$ in Transverse, Away, and Toward regions for $p_{\rm T} >$ 0.5 GeV/$c$. The shaded areas and the error bars around the data points represent the systematic and statistical uncertainties, respectively.

Fig. 5: Number density $N_{\rm ch}$ (left) and $\Sigma p_{\rm T}$ (right) distributions as a function of $p_{\rm T}^{\rm trig}$ in Transverse, Away, and Toward regions for $p_{\rm T} >$ 0.5 GeV/$c$. The shaded areas and the error bars around the data points represent the systematic and statistical uncertainties, respectively.

Fig. 6a: Number density $N_{\rm ch}$ (left) and $\Sigma p_{\rm T}$ (right) distributions as a function of $p_{\rm T}^{\rm trig}$ in Away and Toward regions after the subtraction of Number density $N_{\rm ch}$ and $\Sigma p_{\rm T}$ distributions in the transverse region for pp collisions for $p_{\rm T} >$ 0.5 GeV/$c$. The shaded areas and the error bars around the data points represent the systematic and statistical uncertainties, respectively.

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$\rm{J}/\psi$ production at low transverse momentum in p+p and d+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.C 93 (2016) 064904, 2016.
Inspire Record 1420183 DOI 10.17182/hepdata.73526

We report on the measurement of $\rm{J}/\psi$ production in the dielectron channel at mid-rapidity (|y|<1) in p+p and d+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum $p_{T}$ spectra in p+p for $p_{T}$ < 4 GeV/c and d+Au collisions for $p_{T}$ < 3 GeV/c are presented. These measurements extend the STAR coverage for $\rm{J}/\psi$ production in p+p collisions to low $p_{T}$. The $<p_{T}^{2}>$ from the measured $\rm{J}/\psi$ invariant cross section in p+p and d+Au collisions are evaluated and compared to similar measurements at other collision energies. The nuclear modification factor for $\rm{J}/\psi$ is extracted as a function of $p_{T}$ and collision centrality in d+Au and compared to model calculations using the modified nuclear Parton Distribution Function and a final-state $\rm{J}/\psi$ nuclear absorption cross section.

6 data tables

The mean square of $p_T$.

Nuclear absorption cross section.

The nuclear modicifation factor vs. $p_T$ for $J\psi$ with |y| < 1 in 0-100 percent central d+Au collisions.

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Effect of event selection on jetlike correlation measurement in $d$+Au collisions at $\sqrt{s_{\rm{NN}}}=200$ GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Lett.B 743 (2015) 333-339, 2015.
Inspire Record 1335765 DOI 10.17182/hepdata.73235

Dihadron correlations are analyzed in $\sqrt{s_{_{\rm NN}}} = 200$ GeV $d$+Au collisions classified by forward charged particle multiplicity and zero-degree neutral energy in the Au-beam direction. It is found that the jetlike correlated yield increases with the event multiplicity. After taking into account this dependence, the non-jet contribution on the away side is minimal, leaving little room for a back-to-back ridge in these collisions.

16 data tables

The dihadron correlated yield normalized per radian per unit of pseudorapidity as function of $\Delta\eta$ in d+Au collisions on the near (|$\Delta\phi$| < $\pi$/3). Shown is the low FTPC-Au activity data. Trigger and associated particles have 1 < $p_T$ < 3 GeV/c and |$\eta$| < 1.

The dihadron correlated yield normalized per radian per unit of pseudorapidity as function of $\Delta\eta$ in d+Au collisions on the away side (|$\Delta\phi$ - $\pi$| < $\pi$/3. Shown is the high FTPC-Au activity data. Trigger and associated particles have 1 < $p_T$ < 3 GeV/c and |$\eta$| < 1.

The dihadron correlated yield normalized per radian per unit of pseudorapidity as function of $\Delta\eta$ in d+Au collisions on the near (|$\Delta\phi$| < $\pi$/3) side. Shown is the high-activity data after subtracting the unscaled. Trigger and associated particles have 1 < $p_T$ < 3 GeV/c and |$\eta$| < 1.

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Precision Measurement of the Longitudinal Double-spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at $\sqrt{s}=200$ GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 115 (2015) 092002, 2015.
Inspire Record 1297229 DOI 10.17182/hepdata.73432

We report a new high-precision measurement of the mid-rapidity inclusive jet longitudinal double-spin asymmetry, $A_{LL}$, in polarized $pp$ collisions at center-of-mass energy $\sqrt{s}=200$ GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep inelastic scattering (DIS), semi-inclusive DIS, and RHIC $pp$ data. The measured asymmetries provide evidence for positive gluon polarization in the Bjorken-$x$ region $x>0.05$.

7 data tables

Jet neutral energy fraction (NEF) comparing data with simulations, where both are calculated with pT subtraction. This plot shows 8.4 < $p_T$ < 9.9 GeV/c.

Jet neutral energy fraction (NEF) comparing data with simulations, where both are calculated with pT subtraction. This plot shows 26.8 < $p_T$ < 31.6 GeV/c.

Inclusive jet $A_{LL}$ vs. parton jet $p_T$ for |eta|<0.5.

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Production of pions, kaons and protons in pp collisions at sqrt(s)= 900 GeV with ALICE at the LHC

The ALICE collaboration Aamodt, K. ; Abel, N. ; Abeysekara, U. ; et al.
Eur.Phys.J.C 71 (2011) 1655, 2011.
Inspire Record 885104 DOI 10.17182/hepdata.57568

The production of $\pi^+$, $\pi^-$, $K^+$, $K^-$, p, and pbar at mid-rapidity has been measured in proton-proton collisions at $\sqrt{s} = 900$ GeV with the ALICE detector. Particle identification is performed using the specific energy loss in the inner tracking silicon detector and the time projection chamber. In addition, time-of-flight information is used to identify hadrons at higher momenta. Finally, the distinctive kink topology of the weak decay of charged kaons is used for an alternative measurement of the kaon transverse momentum ($p_{\rm T}$) spectra. Since these various particle identification tools give the best separation capabilities over different momentum ranges, the results are combined to extract spectra from $p_{\rm T}$ = 100 MeV/$c$ to 2.5 GeV/$c$. The measured spectra are further compared with QCD-inspired models which yield a poor description. The total yields and the mean $p_{\rm T}$ are compared with previous measurements, and the trends as a function of collision energy are discussed.

4 data tables

Transverse momentum spectra for positive and negative pions.

Transverse momentum spectra for positive and negative kaons.

Transverse momentum spectra for protons and antiprotons.

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Charged-particle multiplicities in pp interactions at sqrt(s) = 900 GeV measured with the ATLAS detector at the LHC

The ATLAS collaboration Aad, G. ; Abat, E. ; Abbott, B. ; et al.
Phys.Lett.B 688 (2010) 21-42, 2010.
Inspire Record 849050 DOI 10.17182/hepdata.54850

The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range |eta|<2.5 and pT>500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity at eta = 0 is measured to be 1.333 +/- 0.003 (stat.) +/- 0.040 (syst.), which is 5-15% higher than the Monte Carlo models predict.

5 data tables

Average value of charged particle multiplicity per event and unit of pseudorapidity in the pseudorapidity range from -0.2 to 0.2.

Charged particle multiplicity as a function of pseudorapidity.

Charged particle multiplicity as a function of transverse momentum.

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Fragmentation characteristics of relativistic carbon nucleus at its interaction with hydrogen

Belaga, V.V. ; Bondarenko, A.I. ; Karshiev, D.A. ; et al.
Phys.Atom.Nucl. 59 (1996) 991-996, 1996.
Inspire Record 404821 DOI 10.17182/hepdata.38625

None

3 data tables

FRAGB - BEAM FRAGMENT WITH Z>=2.


Fragmentation of a carbon nucleus into three alpha particles at an incident momentum of 4.2-GeV/c per nucleon in a propane bubble chamber.

Belaga, V.V. ; Bondarenko, A.I. ; Kanarek, T. ; et al.
Phys.Atom.Nucl. 59 (1996) 832-840, 1996.
Inspire Record 402733 DOI 10.17182/hepdata.38626

None

1 data table

No description provided.


Rapidity distributions of protons in (p, d, alpha, C) C interactions at 4.2-GeV/c per nucleon

Bekmirzaev, R.N. ; Kladnitskaya, E.N. ; Muminov, M.M. ; et al.
Phys.Atom.Nucl. 58 (1995) 1548-1554, 1995.
Inspire Record 382325 DOI 10.17182/hepdata.38665

None

7 data tables

ASYM is defined as follows: ASYM = (SIG(YRAP(P=3,RF=LAB)<1.1) - (SIG(YRAP(P=3,RF=LAB)>1.1)) / (SIG(YRAP(P=3,RF=LAB)<1.1)+ SIG(YRAP(P=3,RF=LAB)>1.1)).

ASYM is defined as follows: ASYM = (SIG(YRAP(P=3,RF=LAB)<1.1) - (SIG(YRAP( P=3,RF=LAB)>1.1)) / (SIG(YRAP(P=3,RF=LAB)<1.1)+SIG(YRAP(P=3,RF=LAB)>1.1)).

ASYM is defined as follows: ASYM = (SIG(YRAP(P=3,RF=LAB)<1.1) - (SIG(YRAP( P=3,RF=LAB)>1.1)) / (SIG(YRAP(P=3,RF=LAB)<1.1)+SIG(YRAP(P=3,RF=LAB)>1.1)).

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THE STUDY OF NEUTRON INTERACTIONS WITH PROTONS AND CARBON NUCLEI AT p = 4.2-GeV/c

Bekmirzaev, R.N. ; Grishina, O.V. ; Dolejsi, J. ; et al.
JINR-P1-88-617, 1988.
Inspire Record 267743 DOI 10.17182/hepdata.38835

None

5 data tables

No description provided.

No description provided.

No description provided.

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