HEPData Search

First measurements of the W -> lnu and Z/gamma* -> ll (l = e, mu) production cross sections in proton-proton collisions at sqrt(s) = 7 TeV are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W -> lnu and 179 Z/gamma* -> ll candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb-1. The measured total W and Z/gamma*-boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are $\stotW$ * BR(W -> lnu) = 9.96 +- 0.23(stat) +- 0.50(syst) +- 1.10(lumi) nb and $\stotZg$ * BR(Z/gamma* -> ll) = 0.82 +- 0.06(stat) +- 0.05(syst) +- 0.09(lumi) nb (within the invariant mass window 66 < m_ll < 116 GeV). The W/Z cross-section ratio is measured to be 11.7 +- 0.9(stat) +- 0.4(syst). In addition, measurements of the W+ and W- production cross sections and of the lepton charge asymmetry are reported. Theoretical predictions based on NNLO QCD calculations are found to agree with the measurements.

35 data tables

Table 1

Measured fiducial cross section times leptonic branching ratio for W+ production in the W+ -> e+ nu final state.

Table 2

Measured fiducial cross section times leptonic branching ratio for W- production in the W- -> e- nubar final state.

Table 3

Measured fiducial cross section times leptonic branching ratio for W+/- production in the combined W+ -> e+ nu and W- -> e- nubar final state.

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Search for top squark pair production in the dielectron channel

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.

Phys.Rev.D 57 (1998) 589-593, 1998.

Inspire Record 427311 DOI 10.17182/hepdata.41662

This report describes the first search for top squark pair production in the channel stop_1 stopbar_1 -> b bbar chargino_1 chargino_1 -> ee+jets+MEt using 74.9 +- 8.9 pb~-1 of data collected using the D0 detector. A 95% confidence level upper limit on sigma*B is presented. The limit is above the theoretical expectation for sigma*B for this process, but does show the sensitivity of the current D0 data set to a particular topology for new physics.

1 data table

Table 1

Data are extracted from the figure. Sigma*Br.

rivet Analysis
Study of the process $e^+e^-\to\eta\gamma$ in the center-of-mass energy range 1.07--2.00 GeV

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.

Phys.Rev.D 90 (2014) 032002, 2014.

Inspire Record 1275333 DOI 10.17182/hepdata.62279

The $e^+e^-\to\eta\gamma$ cross section has been measured in the center-of-mass energy range 1.07--2.00 GeV using the decay mode $\eta\to 3\pi^0$, $\pi^0\to \gamma\gamma$. The analysis is based on 36 pb$^{-1}$ of integrated luminosity collected with the SND detector at the VEPP-2000 $e^+e^-$ collider. The measured cross section of about 35 pb at 1.5 GeV is explained by decays of the $\rho(1450)$ and $\phi(1680)$ resonances.

2 data tables

Table 1

The energy interval and E+ E- --> ETA GAMMA Born cross section(SIG). The first error in the cross section is statistical, the second systematic. For the last two energy intervals, the upper limits at the 90 PCT confidence level are listed for the cross section.

Table 2

The fitted values of the cross sections at the resonance peaks.

Study of eta pi- production by pions in Coulomb field.

The VES collaboration Amelin, D.V. ; Berdnikov, E.B. ; Bityukov, S.I. ; et al.

363-366, 1998.

Inspire Record 477863 DOI 10.17182/hepdata.41663

The production of eta pi - system at low mass by the pi- beam in the Coulomb field of Be nuclei was studied. The cross section of the reaction pi- Be --> eta pi- Be was compared to the experimental data on the decay eta --> pi+ pi- gamma and to the theoretical predictions.

1 data table

Table 1

Z DEPENDENCE OF DIFFERENTIAL AND TOTAL CROSS-SECTIONS IN QUASIBINARY EXCHANGE REACTIONS ON NUCLEI pi- A(z) ---> (pi0, eta, omega, f2) + A*(z-1) AT 39.1-GeV/c

Apokin, V.D. ; Arestov, Yu.I. ; Belikov, N.I. ; et al.

Sov.J.Nucl.Phys. 46 (1987) 877, 1987.

Inspire Record 239550 DOI 10.17182/hepdata.40837

None

5 data tables

Table 1

Table 2

Table 3

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Polarization Parameters in the Reactions $\pi^- p$ (Polarized) $\to \eta n$ and $\pi^- p$ (Polarized) $\to \eta^\prime n$ at 40-{GeV}/$c$

Apokin, V.D. ; Arestov, Yu.I. ; Avvakumov, I.A. ; et al.

Z.Phys.C 35 (1987) 173, 1987.

Inspire Record 222760 DOI 10.17182/hepdata.40802

The polarization parameter in the reactions π−p→ηn and π−p→η′n at 40 GeV/c with −t ranging from 0 to 2.6 (GeV/c)2 and 1.0 (GeV/c)2, respectively, was measured in experiments using a propanediol polarized target. Only gamma particles from the neutral meson decay were detected. The polarization parameter of the first reaction turns out to be negative in a widet interval (0.05<−t<1.6 (GeV/c)2) and probably changes its sign at larger values oft. The average value of the polarization parameter of the second reaction is equal to −17±8)% in the region 0.05<−t<0.5 (GeV/c)2.

3 data tables

Table 1

Table 2

Table 3

Measurement of single spin asymmetry in eta meson production in p(pol.) p and in anti-p(pol.) p interactions in the beam fragmentation region at 200-GeV/c.

The Fermilab E704 collaboration Adams, D.L. ; Bonner, B.E. ; Corcoran, M.D. ; et al.

Nucl.Phys.B 510 (1998) 3-11, 1998.

Inspire Record 449811 DOI 10.17182/hepdata.51687

We present experimental results on measuring a single spin asymmetry in η-meson production in the interaction of transversely polarized protons and antiprotons at p lab = 200 GeV / c with a proton target in the region 0.2 < x F < 0.7 for p ↑ p , 0.3 < x F < 0.7 for p ̄ ↑p and 0.7 < p T < 2.0 GeV / c . A comparison of single spin asymmetries in π- and η-meson production is made.

2 data tables

Table 1

The true asymmetry for ETA production in proton-proton collisions.

Table 2

The true asymmetry for ETA production in antiproton-proton collisions.

Nuclear modification of electron spectra and implications for heavy quark energy loss in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.

Phys.Rev.Lett. 96 (2006) 032301, 2006.

Inspire Record 695305 DOI 10.17182/hepdata.57257

The PHENIX experiment has measured mid-rapidity transverse momentum spectra (0.4 < p_T < 5.0 GeV/c) of electrons as a function of centrality in Au+Au collisions at sqrt(s_NN)=200 GeV. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of pi^0 and eta mesons, were removed. The resulting non-photonic electron spectra are primarily due to the semi-leptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to non-photonic electrons in p+p collisions. A significant suppression of electrons at high p_T is observed in central Au+Au collisions, indicating substantial energy loss of heavy quarks.

6 data tables

Table 1

Inclusive and non photonic electrons invariant yield versus PT, for minimum bias reactions.

Table 2

Non photonic electrons invariant yield versus PT for different ranges of centrality.

Table 3

Nuclear modification factor as a function of PT, for 0-10% central reactions Note that the systematic error given is related to the the uncertainties in the p+p measurements.An additional systematic error, symmetrical on the + and - side, related to the uncertainties in the Au+Au measurement, is given in the second column. Another, PT-independant, 13%systematic error due to the uncertainty on the overlap function and the Pi0 yield normalization is to add.

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Centrality dependence of charm production from single electrons measurement in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.

Phys.Rev.Lett. 94 (2005) 082301, 2005.

Inspire Record 660611 DOI 10.17182/hepdata.57254

The PHENIX experiment has measured mid-rapidity transverse momentum spectra (0.4 < p_T < 4.0 GeV/c) of single electrons as a function of centrality in Au+Au collisions at sqrt(s_NN) = 200 GeV. Contributions to the raw spectra from photon conversions and Dalitz decays of light neutral mesons are measured by introducing a thin (1.7% X_0) converter into the PHENIX acceptance and are statistically removed. The subtracted ``non-photonic'' electron spectra are primarily due to the semi-leptonic decays of hadrons containing heavy quarks (charm and bottom). For all centralities, charm production is found to scale with the nuclear overlap function, T_AA. For minimum-bias collisions the charm cross section per binary collision is N_cc^bar/T_AA = 622 +/- 57 (stat.) +/- 160 (sys.) microbarns.

18 data tables

Table 1

Value of the Alpha power as used in a fit of dN/dy versus Ncoll of the form A*Ncoll^Alpha, where N is the non photonic electron yield and Ncoll the number of p+p collisions This value only includes data from Au+Au collisions The value of Alpha = 1 is the expectation in the absence of medium effects.

Table 2

Value of the Alpha power as used in a fit of dN/dy versus Ncoll, of the form A*Ncoll^Alpha, where N is the non photonic electron yield and Ncoll the number of p+p collisions This value is calculated including previous data of p+p collisions, measured by PHENIX, in addition of the Au+Au data The value of Alpha = 1 is the expectation in the absence of medium effects.

Table 3

Spectrum in transverse momentum of electrons created in open heavy flavor decays, for minimum bias events.

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Measurement of differential cross sections for charge exchange of $\pi^{-}$ mesons in carbon at 40 GeV/c

Measurement of the W -> lnu and Z/gamma* -> ll production cross sections in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector

Search for top squark pair production in the dielectron channel

rivet Analysis
Study of the process $e^+e^-\to\eta\gamma$ in the center-of-mass energy range 1.07--2.00 GeV

Study of eta pi- production by pions in Coulomb field.

Z DEPENDENCE OF DIFFERENTIAL AND TOTAL CROSS-SECTIONS IN QUASIBINARY EXCHANGE REACTIONS ON NUCLEI pi- A(z) ---> (pi0, eta, omega, f2) + A*(z-1) AT 39.1-GeV/c

Polarization Parameters in the Reactions $\pi^- p$ (Polarized) $\to \eta n$ and $\pi^- p$ (Polarized) $\to \eta^\prime n$ at 40-{GeV}/$c$

Measurement of single spin asymmetry in eta meson production in p(pol.) p and in anti-p(pol.) p interactions in the beam fragmentation region at 200-GeV/c.

Nuclear modification of electron spectra and implications for heavy quark energy loss in Au + Au collisions at s(NN)**(1/2) = 200-GeV.

Centrality dependence of charm production from single electrons measurement in Au + Au collisions at s(NN)**(1/2) = 200-GeV.