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Kinematic distributions and nuclear effects of J/psi production in 920-GeV fixed-target proton-nucleus collisions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Eur.Phys.J. C60 (2009) 525-542, 2009.
Inspire Record 804247 DOI 10.17182/hepdata.57472

Measurements of the kinematic distributions of $J/\psi$ mesons produced in $p-$C, $p-$Ti and $p-$W collisions at $\sqrt{s}=41.6 \mathrm{GeV}$ in the Feynman-$x$ region $-0.34 < x_{F} < 0.14$ and for transverse momentum up to $p_T = 5.4 \mathrm{GeV}/c$ are presented. The $x_F$ and $p_T$ dependencies of the nuclear suppression parameter, $\alpha$, are also given. The results are based on $2.4 \cdot 10^{5}$ $J/\psi$ mesons in both the $e^+ e^-$ and $\mu^{+}\mu^{-}$ decay channels. The data have been collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The measurement explores the negative region of $x_{F}$ for the first time. The average value of $\alpha$ in the measured $x_{F}$ region is $0.981 \pm 0.015$. The data suggest that the strong nuclear suppression of $J/\psi$ production previously observed at high $x_F$ turns into an enhancement at negative $x_F$.

4 data tables

J/PSI distributions (dN/dp_T, normalized to their integrals over the measured range) for three targets materials with statistical and systematics uncertainties.

J/PSI distributions (dN/dx_F, normalized to their integrals over the measured range) for three targets materials with statistical and systematics uncertainties.

The parameter Alpha as a function of p_T. Statistical and systematic uncertainties are indicated separately.

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Angular distributions of leptons from $J/\psi$ ' $s$ produced in 920 GeV fixed-target proton-nucleus collisions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Eur.Phys.J. C60 (2009) 517-524, 2009.
Inspire Record 810555 DOI 10.17182/hepdata.57473

A study of the angular distributions of leptons from decays of J/psi's produced in p-C and p-W collisions at sqrt{s}=41.6 GeV has been performed in the Feynman-x region -0.34 < x_F < 0.14 and for transverse momentum up to 5.4 GeV/c. The data were collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The results, based on a clean selection of 2.3 x 10^5 J/psi's reconstructed in both the e^+ e^- and mu^+ mu^- decay channels, indicate that J/psi's are produced with longitudinal polarization. The magnitude of the effect is maximal at low p_T. For p_T >1 GeV/c a significant dependence on the reference frame is found: the polar anisotropy is more pronounced in the Collins-Soper frame and almost vanishes in the helicity frame, where, instead, a significant azimuthal anisotropy arises.

9 data tables

Output parameters obtained by fitting the distributions.

Values of the parameters Lambda_theta, Lambda_phi et Lambda_theta_phi measured in the Collins-Soper frame as functions of the average reconstructed p_T for combined carbon and tungsten data.

Values of the parameters Lambda_theta, Lambda_phi et Lambda_theta_phi measured in the Collins-Soper frame as functions of the average reconstructed x_F for combined carbon and tungsten data.

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Production of the Charmonium States $\chi_{c1}$ and $\chi_{c2}$ in Proton Nucleus Interactions at $\sqrt{s}$ = 41.6-GeV

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Phys.Rev. D79 (2009) 012001, 2009.
Inspire Record 790682 DOI 10.17182/hepdata.57464

A measurement of the ratio R_chic = (chic -> Jpsi + gam)/ Jpsi in pC, pTi and pW interactions at 920 GeV/c (sqrt{s}=41.6 GeV) in the Feynman-x range -0.35 < x_F(Jpsi) < 0.15 is presented. Both mu+mu- and e+e- Jpsi decay channels are observed with an overall statistics of about 15000 chic events, which is by far the largest available sample in pA collisions. The result is R_chic = 0.188+-0.013(st)(+0.024)(-0.022)(sys) averaged over the different materials, when no Jpsi and chic polarisations are considered. The chic_1 to chic_2 production ratio R_12 = R_chic1/R_chic2 is measured to be 1.02+-0.40, leading to a cross section ratio sigma(chic_1)/sigma(chic_2)=0.57+-0.23. The dependence of R_chic on the Feynman-x of the Jpsi, x_F(Jpsi), and its transverse momentum, p_T(Jpsi), is studied, as well as its dependence on the atomic number, A, of the target. For the first time, an extensive study of possible biases on R_chic and R_12 due to the dependence of acceptance on the polarization states of Jpsi and chic is performed. By varying the polarisation parameter, lambda(obs), of all produced Jpsi's by two sigma around the value measured by HERA-B, and considering the maximum variation due to the possible chic_1 and chic_2 polarisations, it is shown that R_chic could change by a factor between 1.02 and 1.21 and R_12 by a factor between 0.89 and 1.16.

3 data tables

Measurement of R_CHI/C in <E+ E->, <MU+ MU-> and combined channel.

Measurement of R_12 in <E+ E->, <MU+ MU-> and combined channel.

Measurement of SIG(C1)/SIG(C2) in <E+ E->, <MU+ MU-> and combined channel.


J/psi and psi-prime production and their normal nuclear absorption in proton-nucleus collisions at 400-GeV

The NA50 collaboration Alessandro, B. ; Alexa, C. ; Arnaldi, R. ; et al.
Eur.Phys.J. C48 (2006) 329, 2006.
Inspire Record 733916 DOI 10.17182/hepdata.57412

We report a new measurement of J/psi, psi' and Drell-Yan cross-sections, in the kinematical domain $-0.425&lt;y_{\rm cm}&lt;0.575$ and $-0.5&lt;\cos\theta_{\rm CS}&lt;0.5$, performed at the CERN-SPS using 400 GeV/c incident protons on Be, Al, Cu, Ag, W and Pb targets. The dependence of the charmonia production cross-sections on the size of the target nucleus allows to quantify the so-called normal nuclear absorption. In the framework of the Glauber model, this new measurement is combined with results previously obtained with the same apparatus, under different experimental conditions, and leads to a precise determination of the J/psi and psi' absorption cross-sections in the surrounding nuclear matter.

4 data tables

Production cross sections, per taregt nucleon for J/PSI and PSI(3685) and for Drell-Yann dimuon in the mass range of 2.9-4.5 GeV/c**, integrated in the phase space windows of the measurement.

Ratios of J/PSI, PSI(3685) and Drel Yann production cross sections, and for Drell-Yann dimuon in the mass range of 2.9-4.5 GeV/c**, integrated in the phase space windows of the measurement.

Absorption cross-section obtained with Glauber fits results only from this analysis.

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Improved measurement of the b-anti-b production cross section in 920-GeV fixed-target proton-nucleus collisions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Phys.Rev. D73 (2006) 052005, 2006.
Inspire Record 700310 DOI 10.17182/hepdata.57501

A new measurement of the b-bbar production cross section in 920 GeV proton-nucleus collisions is presented by the HERA-B collaboration. The b-bbar production is tagged via inclusive bottom quark decays into J/psi mesons, by exploiting the longitudinal separation of J/psi->ll decay vertices from the primary proton-nucleus interaction point. Both e+e- and mu+mu- channels are reconstructed, for a total of 83 +- 12 inclusive b->J/psi X events found. The combined analysis yields a b-bbar to prompt J/psi cross section ratio of ${\frac{{\Delta\sigma(bbbar)}}{{\Delta\sigma_{\jpsi}}}} = 0.032\pm 0.005 \stat \pm 0.004 \sys$ measured in the x_f acceptance (-0.35 <x_f <0.15), extrapolated to $\sigma(bbbar) = 14.9 \pm 2.2 \stat \pm 2.4 \sys $ nb/nucleon in the total phase space.

7 data tables

Ratio of prompt J/PSI to B-BBAR production cross section in P C interactions in the Feynmann X range -0.35 to 0.15 for the E+ E- and MU+ MU- channels separately and combined.

Ratio of prompt J/PSI to B-BBAR production cross section in P TI interactions in the Feynmann X range -0.35 to 0.15 for the E+ E- and MU+ MU- channels separately and combined.

Ratio of prompt J/PSI to B-BBAR production cross section in P WT interactions in the Feynmann X range -0.35 to 0.15 for the E+ E- and MU+ MU- channels separately and combined.

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Measurement of the $J/\psi$ production cross section in 920-GeV/c fixed-target proton-nucleus interactions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Phys.Lett. B638 (2006) 407-414, 2006.
Inspire Record 700309 DOI 10.17182/hepdata.57500

The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production cross sections of J/Psi mesons are measured in proton-nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The J/Psi mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46 nb/nucleon. In addition, our result is compared with previous measurements.

4 data tables

Cross section for the individual targets for the visible rapidity region.

Total cross section for the individual targets extrapolated to the full phase space.

Total cross section for P NUCLEON --> J/PSI X for the full phase space.

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Charmonia and Drell-Yan production in proton-nucleus collisions at the CERN SPS

The NA50 collaboration Alessandro, B. ; Alexa, C. ; Arnaldi, R. ; et al.
Phys.Lett. B553 (2003) 167-178, 2003.
Inspire Record 612573 DOI 10.17182/hepdata.29487
5 data tables

The J/PSI production cross section times the branching ratio to MU+ MU- pernucleon-nucleon collision for the differential nuclear targets.

The PSI(3685) production cross section times the branching ratio to MU+ MU-per nucleon-nucleon collision for the differential nuclear targets.

The Drell Yan cross section, divided by the mass number A, and multiplied by the isospin correction factors in the mass interval 2.9 to 4.5 GeV.

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Charmonium production and nuclear absorption in p A interactions at 450-GeV

The NA50 collaboration Alessandro, B. ; Alexa, C. ; Arnaldi, R. ; et al.
Eur.Phys.J. C33 (2004) 31-40, 2004.
Inspire Record 629957 DOI 10.17182/hepdata.30011
13 data tables

The J/PSI production cross sections, per target nucleon, times the di-muon branching ratio for the two data samples.

The PSI(3685) production cross sections, per target nucleon, times the di-muon branching ratio for the two data samples.

J/PSI production cross section times the di-muon branching ratio for the BEtarget as a function of the Feynman X bin.

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Measurement of J / psi and psi-prime suppression in p-A collisions at 800-GeV/c

The NuSea collaboration Leitch, M.J. ; Lee, W.M. ; Beddo, M.E. ; et al.
Phys.Rev.Lett. 84 (2000) 3256-3260, 2000.
Inspire Record 507188 DOI 10.17182/hepdata.55127

Measurements of the suppression of the yield per nucleon of J/Psi and Psi' production for 800 GeV/c protons incident on heavy relative to light nuclear targets have been made with very broad coverage in xF and pT. The observed suppression is smallest at xF values of 0.25 and below and increases at larger values of xF. It is also strongest at small pT. Substantial differences between the Psi' and J/Psi are observed for the first time in p-A collisions. The suppression for the Psi' is stronger than that for the J/Psi for xF near zero, but becomes comparable to that for the J/Psi for xF > 0.6.

5 data tables

Target Atomic Mass dependence expressed as the POWER for J/PSI production. X2 is the momentum fraction of the struck quark.

Target Atomic Mass dependence expressed as the POWER for PSIPRIME production. X2 is the momentum fraction of the struck quark.

PT dependence of ALPHA for J/PSI and PSIPRIME production for the small-XF dataset.

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Charmonia production in 450-GeV/c proton induced reactions

The NA38 collaboration Abreu, M.C. ; Baglin, C. ; Baldit, A. ; et al.
Phys.Lett. B444 (1998) 516-522, 1998.
Inspire Record 478387 DOI 10.17182/hepdata.49294
5 data tables

The ratio of the production cross sections, in the di-muon channel. Note that there are wo set of CU and WT data with targets of different lengths. An average values is also given for these.

The J/PSI absolute cross sections, times the BR to di-muons.

The PSI(3685) absolute cross sections, times the BR to di-muons.

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