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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.C 60 (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
Table 1

Output parameters obtained by fitting the distributions.

Table 2

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.

Table 3

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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Measurement of the t anti-t Production Cross Section in 2 fb**-1 of p anti-p Collisions at s**(1/2) =1.96-TeV Using Lepton Plus Jets Events with Soft Muon b-Tagging

The CDF collaboration Aaltonen, T. ; Adelman, Jahred A. ; Akimoto, T. ; et al.
Phys.Rev.D 79 (2009) 052007, 2009.
Inspire Record 811890 DOI 10.17182/hepdata.57018

We present a measurement of the $\ttbar$ production cross section in $\ppbar$ collisions at $\sqrt{s}=1.96$ TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with $\ttbar$ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF Run II data sample corresponding to $2 \mathrm{fb^{-1}}$ of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of $79.5\pm5.3$ events, we measure a production cross section of $9.1\pm 1.6 \mathrm{pb}$.

1 data table
Table 1

Measured cross section assuming a top quark mass of 175 GeV. The second systematic error is the uncertainty on the luminosity.


Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions IV: Copper nuclei and beam momenta from +/-3 GeV/c to +/-15 GeV/c

The HARP-CDP collaboration Bolshakova, A. ; Boyko, I. ; Chelkov, G. ; et al.
Eur.Phys.J.C 64 (2009) 181-241, 2009.
Inspire Record 823636 DOI 10.17182/hepdata.52601

We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary copper target, of proton and pion beams with momentum from +/-3 GeV/c to +/-15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees.

365 data tables
Table 1

Measured cross section as a function of PT for P production from a P beam of momentum 3 GeV/c in the angular range 20 to 30 DEG.

Table 2

Measured cross section as a function of PT for P production from a P beam of momentum 3 GeV/c in the angular range 30 to 40 DEG.

Table 3

Measured cross section as a function of PT for P production from a P beam of momentum 3 GeV/c in the angular range 40 to 50 DEG.

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Cross-Sections of Large-Angle Hadron Production in Proton- and Pion-Nucleus Interactions III: Tantalum Nuclei and Beam Momenta from +/-3 Gev/c to +/-15 Gev/c

The HARP-CDP collaboration Bolshakova, A. ; Boyko, I. ; Chelkov, G. ; et al.
Eur.Phys.J.C 63 (2009) 549-609, 2009.
Inspire Record 822058 DOI 10.17182/hepdata.50528

We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary tantalum target, of proton and pion beams with momentum from +/-3 GeV/c to +/-15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees. They are of particular relevance for the optimization of the design parameters of the proton driver of a neutrino factory.

375 data tables
Table 1

Measured cross section as a function of PT for P production from a P beam of momentum 3 GeV/c in the angular range 20 to 30 DEG.

Table 2

Measured cross section as a function of PT for P production from a P beam of momentum 3 GeV/c in the angular range 30 to 40 DEG.

Table 3

Measured cross section as a function of PT for P production from a P beam of momentum 3 GeV/c in the angular range 40 to 50 DEG.

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A Precision Measurement of the Inclusive ep Scattering Cross Section at HERA

The H1 collaboration Aaron, F.D. ; Alexa, C. ; Alimujiang, K. ; et al.
Eur.Phys.J.C 64 (2009) 561-587, 2009.
Inspire Record 818546 DOI 10.17182/hepdata.54873

A measurement of the inclusive deep-inelastic neutral current e+p scattering cross section is reported in the region of four-momentum transfer squared, 12&lt;=Q^2&lt;=150 GeV^2, and Bjorken x, 2x10^-4&lt;=x&lt;=0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E_e=27.6 GeV and E_p=920 GeV, respectively. The data are combined with previously published data, taken at E_p=820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data.

42 data tables
Table 1

Data from the 2000 running period at Q**2 There is an additional 1.2 PCT overall normalisation uncertainty not included.

Table 2

Data from the 2000 running period at Q**2 There is an additional 1.2 PCT overall normalisation uncertainty not included.

Table 3

Data from the 2000 running period at Q**2 There is an additional 1.2 PCT overall normalisation uncertainty not included.

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Photoproduction of pi^0 eta on protons and the Delta(1700)D_{33} resonance

The Crystal Ball at MAMI & TAPS & A2 collaborations Kashevarov, V.L. ; Fix, A. ; Aguar-Bartolome, P. ; et al.
Eur.Phys.J.A 42 (2009) 141-149, 2009.
Inspire Record 811783 DOI 10.17182/hepdata.52974

Total and differential cross sections for the reaction gamma p -> pi^o eta p have been measured with the Crystal Ball/TAPS detector using the tagged photon facility at the MAMI C accelerator in Mainz. In the energy range E_gamma=0.95-1.4 GeV the reaction is dominated by the excitation and sequential decay of the Delta(1700)D33 resonance. Angular distributions measured with high statistics allow us to determine the ratio of hadronic decay widths \Gamma_{\eta \Delta}/\Gamma_{\pi S11} and the ratio of the helicity amplitudes A_{3/2}/A_{1/2} for this resonance.

5 data tables
Table 1

Total cross section for the GAMMA P --> PI0 ETA P reaction.. Statistical erros only.

Table 2

The differential cross section as a function of cos(theta(pi0) in the canonical(K) reference frame.. Statistical erros only.

Table 3

The differential cross section as a function of phi(pi0) in the canonical(K) reference frame.. Statistical erros only.

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Events with Isolated Leptons and Missing Transverse Momentum and Measurement of W Production at HERA

The H1 collaboration Aaron, F.D. ; Alexa, C. ; Andreev, V. ; et al.
Eur.Phys.J.C 64 (2009) 251-271, 2009.
Inspire Record 810292 DOI 10.17182/hepdata.53047

Events with high energy isolated electrons, muons or tau leptons and missing transverse momentum are studied using the full e^\pm p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb^{-1}. Within the Standard Model, events with isolated leptons and missing transverse momentum mainly originate from the production of single W bosons. The total single W boson production cross section is measured as 1.14 \pm 0.25 (stat.) \pm 0.14 (sys.) pb, in agreement with the Standard Model expectation. The data are also used to establish limits on the WW\gamma gauge couplings and for a measurement of the W boson polarisation.

2 data tables
Table 1

Total single W boson production cross section.

Table 2

Differential single W boson production cross section.


Jet Production in ep Collisions at High Q^2 and Determination of alpha_s

The H1 collaboration Aaron, F.D. ; Alexa, C. ; Alimujiang, K. ; et al.
Eur.Phys.J.C 65 (2010) 363-383, 2010.
Inspire Record 818707 DOI 10.17182/hepdata.70833

The production of jets is studied in deep-inelastic ep scattering at large negative four momentum transfer squared 150&lt;Q^2&lt;15000 GeV^2 using HERA data taken in 1999-2007, corresponding to an integrated luminosity of 395 pb^-1. Inclusive jet, 2-jet and 3-jet cross sections, normalised to the neutral current deep-inelastic scattering cross sections, are measured as functions of Q^2, jet transverse momentum and proton momentum fraction. The measurements are well described by perturbative QCD calculations at next-to-leading order corrected for hadronisation effects. The strong coupling as determined from these measurements is alpha_s(M_Z) = 0.1168 +/-0.0007 (exp.) +0.0046/-0.0030 (th.) +/-0.0016(pdf).

7 data tables
Table 1

Normalised inclusive jet cross section in bins of $Q^{2}$.

Table 2

Normalised 2-jet cross section in bins of $Q^{2}$.

Table 3

Normalised 3-jet cross section in bins of $Q^{2}$.

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Nuclear stopping and rapidity loss in Au+Au collisions at sqrt{s_{NN}}=62.4 GeV

The BRAHMS collaboration Arsene, I.C. ; Bearden, I.G. ; Beavis, D. ; et al.
Phys.Lett.B 677 (2009) 267-271, 2009.
Inspire Record 810481 DOI 10.17182/hepdata.89449

Transverse momentum spectra of protons and anti-protons measured in the rapidity range 0<y<3.1 from 0-10% central Au+Au collisions at sqrt{s_{NN}}=62.4 GeV are presented. The rapidity densities, dN/dy, of protons, anti-protons and net-protons N()p-N(pbar) have been deduced from the spectra over a rapidity range wide enough to observe the expected maximum net-baryon density. From mid-rapidity to y=1 the net-proton yield is roughly constant (dN/dy ~ 10),but rises to dN/dy ~25 at 2.3<y<3.1. The mean rapidity loss is 2.01 +-0.16 units from beam rapidity. The measured rapidity distributions are compared to model predictions. Systematics of net-baryon distributions and rapidity loss vs. collision energy are discussed.

16 data tables
Table 1a

$\frac{1}{2\pi p_{\mathrm{T}}}\frac{\mathrm{d}^2N}{\mathrm{d}p_{\mathrm{T}}\mathrm{d}y}$ versus $p_{\mathrm{T}}$ for $\mathrm{p}$ in $\mathrm{Au}-\mathrm{Au}$ at $\sqrt{s_{\mathrm{NN}}}=62.4\,\mathrm{Ge\!V}$ near $y=-0.1-0.1$

Table 1b

$\frac{1}{2\pi p_{\mathrm{T}}}\frac{\mathrm{d}^2N}{\mathrm{d}p_{\mathrm{T}}\mathrm{d}y}$ versus $p_{\mathrm{T}}$ for $\overline{\mathrm{p}}$ in $\mathrm{Au}-\mathrm{Au}$ at $\sqrt{s_{\mathrm{NN}}}=62.4\,\mathrm{Ge\!V}$ near $y=-0.1-0.1$

Table 1c

$\frac{1}{2\pi p_{\mathrm{T}}}\frac{\mathrm{d}^2N}{\mathrm{d}p_{\mathrm{T}}\mathrm{d}y}$ versus $p_{\mathrm{T}}$ for $\mathrm{p}$ in $\mathrm{Au}-\mathrm{Au}$ at $\sqrt{s_{\mathrm{NN}}}=62.4\,\mathrm{Ge\!V}$ near $y=0.4-0.9$

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K/pi Fluctuations at Relativistic Energies

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 103 (2009) 092301, 2009.
Inspire Record 810902 DOI 10.17182/hepdata.98971

We report results for $K/\pi$ fluctuations from Au+Au collisions at $\sqrt{s_{NN}}$ = 19.6, 62.4, 130, and 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider. Our results for $K/\pi$ fluctuations in central collisions show little dependence on the incident energies studied and are on the same order as results observed by NA49 at the Super Proton Synchrotron in central Pb+Pb collisions at $\sqrt{s_{NN}}$ = 12.3 and 17.3 GeV. We also report results for the collision centrality dependence of $K/\pi$ fluctuations as well as results for $K^{+}/\pi^{+}$, $K^{-}/\pi^{-}$, $K^{+}/\pi^{-}$, and $K^{-}/\pi^{+}$ fluctuations. We observe that the $K/\pi$ fluctuations scale with the multiplicity density, $dN/d\eta$, rather than the number of participating nucleons.

5 data tables
Figure 1

(Color online) The event-by-event $K/\pi$ ratio for 200 GeV Au+Au central collisions (0-5%) compared with the same quantity calculated from mixed events. The inset shows the ratio of the distribution from real events to that from mixed events. The errors shown are statistical.

Figure 1 inset

(Color online) The event-by-event $K/\pi$ ratio for 200 GeV Au+Au central collisions (0-5%) compared with the same quantity calculated from mixed events. The inset shows the ratio of the distribution from real events to that from mixed events. The errors shown are statistical.

Figure 2

(Color online) Measured dynamical $K/\pi$ fluctuations in terms of σdyn for central collisions (0 - 5%) of 19.6, 62.4, 130, and 200 GeV Au+Au compared with the central collisions (0 - 3.5%) of Pb+Pb from NA49 [7] and the statistical hadronization (SH) model of Ref. [14]. The solid line represents the relationship of the incident energy dependence of $\sigma_{dyn}$ in central collisions to the collision centrality dependence of $\nu_{dyn,K\pi}$ at higher energies. Both statistical (vertical line with horizontal bar) and systematic (no vertical line) error bars are shown for the experimental data.

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