HEPData Search

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Simultaneous multiplicity and forward energy characterization of particle spectra in Au + Au collisions at 11.6-A-GeV/c.

The E-802 collaboration Ahle, L. ; Akiba, Y. ; Ashktorab, K. ; et al.

Phys.Rev.C 59 (1999) 2173-2188, 1999.

Inspire Record 501648 DOI 10.17182/hepdata.4988

In this paper Au+Au collisions at 11.6A GeV/c are characterized by two global observables: the energy measured near zero degrees (EZCAL) and the total event multiplicity. Particle spectra are measured for different event classes that are defined in a two-dimensional grid of both global observables. For moderately central events (σ/σint<12%) the proton dN/dy distributions do not depend on EZCAL but only on the event multiplicity. In contrast the shape of the proton transverse spectra shows little dependence on the event multiplicity. The change in the proton dN/dy distributions suggests that different conditions are formed in the collision for different event classes. These event classes are studied for signals of new physics by measuring pion and kaon spectra and yields. In the event classes doubly selected on EZCAL and multiplicity there is no indication of any unusual pion or kaon yields, spectra, or K/π ratio even in the events with extreme multiplicity.

48 data tables match query

Table 1

Table for event classification (from CLASS1 to CLASS8) where ZCAL energy solely used for event selection. Number of Projectile Participants Npp=197*(1-E(P=3)/EKIN(P=1)).

Table 2

CLASS1 (see Table for event classification).

Table 3

CLASS1 (see Table for event classification).

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Exclusive measurement of two-pion production in the dd --> 4Hepipi reaction

Keleta, S. ; Bargholtz, Chr. ; Bashkanov, M. ; et al.

Nucl.Phys.A 825 (2009) 71-90, 2009.

Inspire Record 818215 DOI 10.17182/hepdata.52982

The results from the first kinematically complete measurement of the dd --> 4Hepipi reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar pipi-invariant mass distributions appearing in double pion production in light ion collisions, the so-called ABC effect. The measurements were performed at the incident deuteron energies of 712 MeV and 1029 MeV, with the WASA detector assembly at CELSIUS in Uppsala, Sweden. We report the observation of a characteristic enhancement at low pipi-invariant mass at 712 MeV, the lowest energy yet. At the higher energy, in addition to confirming previous experimental observations, our results reveal a strong angular dependence of the pions in the overall centre of mass system. The results are qualitatively reproduced by a theoretical model, according to which the ABC effect is described as resulting from a kinematical enhancement in the production of the pion pairs from two parallel and independent NN--> dpi sub-processes.

15 data tables match query

Table 1

Total cross section for neutral and charged pion channels.

Table 2

Invariant PI0 PI0 mass distribution at deuteron kinetic energy 1.029 GeV.

Table 3

Invariant PI+ PI- mass distribution at deuteron kinetic energy 1.029 GeV.

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Reaction cross sections for 65 MeV protons on targets from $^9$Be to $^{208}$Pb

Ingemarsson, A. ; Nyberg, J. ; Renberg, P.U. ; et al.

Nucl.Phys.A 653 (1999) 341-354, 1999.

Inspire Record 1389640 DOI 10.17182/hepdata.36231

Reaction cross sections for 65.5 MeV protons have been measured for 9 Be, 12 C, 16 O, 28 Si, 40 Ca, 58,60 Ni, 112.116.118.120.124 Sn, and 208 Pb. The results are compared with optical model predictions using relativistic global potentials.

13 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Reaction cross-sections for 38, 65, and 97 MeV deuterons on targets from Be-9 to Pb-208

Auce, A. ; Carlson, R.F. ; Cox, A.J. ; et al.

Phys.Rev.C 53 (1996) 2919-2925, 1996.

Inspire Record 433953 DOI 10.17182/hepdata.25858

1 data table match query

Table 1

No description provided.

Measurement of prompt photon production in $\sqrt{s_\mathrm{NN}} = 8.16$ TeV $p$+Pb collisions with ATLAS

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.

Phys.Lett.B 796 (2019) 230-252, 2019.

Inspire Record 1723858 DOI 10.17182/hepdata.87256

The inclusive production rates of isolated, prompt photons in $p$+Pb collisions at $\sqrt{s_\mathrm{NN}} = 8.16$ TeV are studied with the ATLAS detector at the Large Hadron Collider using a dataset with an integrated luminosity of 165 nb$^{-1}$ recorded in 2016. The cross-section and nuclear modification factor $R_{p\mathrm{Pb}}$ are measured as a function of photon transverse energy from 20 GeV to 550 GeV and in three nucleon-nucleon centre-of-mass pseudorapidity regions, (-2.83,-2.02), (-1.84,0.91), and (1.09,1.90). The cross-section and $R_{p\mathrm{Pb}}$ values are compared with the results of a next-to-leading-order perturbative QCD calculation, with and without nuclear parton distribution function modifications, and with expectations based on a model of the energy loss of partons prior to the hard scattering. The data disfavour a large amount of energy loss and provide new constraints on the parton densities in nuclei.

3 data tables match query

Table 1

The measured cross sections for prompt, isolated photons with rapidity in (1.09,1.90).

Table 2

The measured cross sections for prompt, isolated photons with rapidity in (−1.84,0.91).

Table 3

The measured cross sections for prompt, isolated photons with rapidity in (−2.83,−2.02).

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.

Nature Phys. 13 (2017) 852-858, 2017.

Inspire Record 1512305 DOI 10.17182/hepdata.77761

Light-by-light scattering ($\gamma\gamma\rightarrow\gamma\gamma$) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead (Pb) ions. Using 480 $\mu$b$^{-1}$ of Pb+Pb collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, the ATLAS Collaboration reports evidence for the $\gamma\gamma\rightarrow\gamma\gamma$ reaction. A total of 13 candidate events are observed with an expected background of 2.6$\pm$0.7 events. After background subtraction and analysis corrections, the fiducial cross section of the process $\textrm{Pb+Pb}\,(\gamma\gamma)\rightarrow \textrm{Pb}^{(\ast)}\textrm{+}\textrm{Pb}^{(\ast)}\,\gamma\gamma$, for photon transverse energy $E_{\mathrm{T}}>$3 GeV, photon absolute pseudorapidity $|\eta|<$2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 $\pm$ 24 (stat.) $\pm$ 17 (syst.) nb, which is in agreement with Standard Model predictions.

3 data tables match query

Table 2

Detector-level diphoton invariant mass distribution

Table 1

Detector-level diphoton acoplanarity distribution

Table 3

The measured total fiducial cross section

A New measurement of the Pontecorvo reaction anti-p + d ---> pi- + p with the OBELIX spectrometer at LEAR

The OBELIX collaboration Ableev, V.G. ; Adamo, A. ; Agnello, M. ; et al.

Nucl.Phys.A 562 (1993) 617-643, 1993.

Inspire Record 364197 DOI 10.17182/hepdata.3849

Antinucleon-nucleus annihilations into two-body final states containing only one or no meson are unusual annihilations (Pontecorvo reactions), practically unexplored experimentally, with the exception of the channel p d → π − p , for which only two low-statistics measurements exist. Their physical interest lies in the possibility of exploring small-distance nuclear dynamics, in which an important role can be played by non-nucleonic degrees of freedom. A new measurement of the p d → π − p reaction rate at rest, performed with the OBELIX spectrometer at LEAR, with the best statistics up to now and a careful evaluation of systematic effects is reported, together with a critical analysis of the existing theoretical models. The measured branching ratio, which confirms the previous results, can represent a reference point for the studies in the field.

1 data table match query

Table 1

No description provided.

THE STUDY OF INCLUSIVE CHARACTERISTICS OF anti-d d INTERACTIONS AT 12-GeV/c

Batyunya, B.V. ; Boguslavsky, I.V. ; Bruncko, D. ; et al.

JINR-P1-87-849, 1987.

Inspire Record 253758 DOI 10.17182/hepdata.9416

None

8 data tables match query

Table 1

THE BETTER FIT FOR PI- AND BARIONBAR IS THE SUM OF TWO EXPONENT: A*EXP(-B1*PT**2)+D*EXP(-B2*PT**2).FOR PI- B1=30+-4 AND B2=6.3+-.3 .FOR BARIONBAR B1=46+-18 AND B2=3.9+-.5.

Table 2

No description provided.

Table 3

No description provided.