Study of fermion pair production in $e^{+} e^{-}$ collisions at 130-GeV to 183-GeV

The ALEPH collaboration Barate, R. ; Decamp, D. ; Ghez, Philippe ; et al.
Eur.Phys.J. C12 (2000) 183-207, 2000.
Inspire Record 498072 DOI 10.17182/hepdata.49128

The cross sections and forward-backward asymmetries of hadronic and leptonic events produced in e+e- collisions at centre-of-mass energies of 130-183 GeV are presented. Results for ee, mumu, tautau, qq, bb and cc production show no significant deviation from the Standard Model predictions. This enable constraints to be set upon physics beyond the Standard Model such as four-fermion contact interactions, leptoquarks, Z' bosons and R-parity violating squarks and sneutrinos. Limits on the energy scale Lambda of eeff contact interactions are typically in the range from 2-10 TeV. Limits on R-parity violating sneutrinos reach masses of a few hundred GeV for large values of their Yukawa couplings.

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Measurement of the muon charge asymmetry in inclusive $pp \to W+X$ production at $\sqrt s =$ 7 TeV and an improved determination of light parton distribution functions

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Rev. D90 (2014) 032004, 2014.
Inspire Record 1273570 DOI 10.17182/hepdata.65456

Measurements of the muon charge asymmetry in inclusive pp to WX production at sqrt(s) = 7 TeV are presented. The data sample corresponds to an integrated luminosity of 4.7 inverse femtobarns recorded with the CMS detector at the LHC. With a sample of more than twenty million W to mu nu events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10E-3 to 10E-1. These measurements and the recent CMS measurement of associated W + charm production are used together with the cross sections for inclusive deep inelastic ep scattering at HERA in a next-to-leading-order QCD analysis. The determination of the valence quark distributions is improved, and the strange-quark distribution is probed directly through the leading-order process g + s to W + c in proton-proton collisions at the LHC.

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Forward-backward asymmetry of Drell-Yan lepton pairs in $pp$ collisions at $\sqrt{s} = 7$ TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Lett. B718 (2013) 752-772, 2013.
Inspire Record 1122847 DOI 10.17182/hepdata.65322
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Measurement of the electron charge asymmetry in inclusive $W$ production in $pp$ collisions at $\sqrt{s}=7$ TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Rev.Lett. 109 (2012) 111806, 2012.
Inspire Record 1118047 DOI 10.17182/hepdata.66333

A measurement of the electron charge asymmetry in inclusive pp to W + X to e nu + X production at sqrt(s) = 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 840 inverse picobarns. The electron charge asymmetry reflects the unequal production of positive and negative W bosons in pp collisions. The electron charge asymmetry is measured in bins of absolute value of electron pseudorapidity in the range of abs(eta) < 2.4. The asymmetry rises from about 0.1 to 0.2 as a function of the pseudorapidity and is measured with a relative precision better than 7%. This measurement provides new stringent constraints for parton distribution functions.

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Measurements of the $t\bar{t}$ charge asymmetry using the dilepton decay channel in pp collisions at $\sqrt{s} =$ 7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
JHEP 1404 (2014) 191, 2014.
Inspire Record 1281538 DOI 10.17182/hepdata.64729
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Forward–backward asymmetry of Drell–Yan lepton pairs in pp collisions at $\sqrt{s} = 8$ $\,\mathrm{TeV}$

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J. C76 (2016) 325, 2016.
Inspire Record 1415949 DOI 10.17182/hepdata.73121

A measurement of the forward–backward asymmetry ${A}_{\mathrm{FB}}$ of oppositely charged lepton pairs ( $\mu \mu $ and $\mathrm{e}\mathrm{e}$ ) produced via $\mathrm{Z}/\gamma ^*$ boson exchange in pp collisions at $\sqrt{s} = 8$ $\,\mathrm{TeV}$ is presented. The data sample corresponds to an integrated luminosity of 19.7 $\,\mathrm{fb}^{-1}$ collected with the CMS detector at the LHC. The measurement of ${A}_{\mathrm{FB}}$ is performed for dilepton masses between 40 $\,\text {GeV}$ and 2 $\,\mathrm{TeV}$ and for dilepton rapidity up to 5. The ${A}_{\mathrm{FB}}$ measurements as a function of dilepton mass and rapidity are compared with the standard model predictions.

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Inclusive and differential measurements of the $t\overline{t}$ charge asymmetry in pp collisions at $\sqrt{s} =$ 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett. B757 (2016) 154-179, 2016.
Inspire Record 1382590 DOI 10.17182/hepdata.68759
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Measurement of the charge asymmetry in top quark pair production in pp collisions at $\sqrt(s) =$ 8 TeV using a template method

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev. D93 (2016) 034014, 2016.
Inspire Record 1388178 DOI 10.17182/hepdata.69208
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Measurement of the $\Lambda_b$ polarization and angular parameters in $\Lambda_b\to J/\psi\, \Lambda$ decays from pp collisions at $\sqrt{s}=$ 7 and 8 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev. D97 (2018) 072010, 2018.
Inspire Record 1654926 DOI 10.17182/hepdata.83664

An analysis of the bottom baryon decay Λb→J/ψ(→μ+μ-)Λ(→pπ-) is performed to measure the Λb polarization and three angular parameters in data from pp collisions at s=7 and 8 TeV, collected by the CMS experiment at the Large Hadron Collider. The Λb polarization is measured to be 0.00±0.06(stat)±0.06(syst) and the parity-violating asymmetry parameter is determined to be 0.14±0.14(stat)±0.10(syst). The measurements are compared to various theoretical predictions, including those from perturbative quantum chromodynamics.

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Measurement of the inclusive leptonic asymmetry in top-quark pairs that decay to two charged leptons at CDF

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev.Lett. 113 (2014) 042001, 2014.
Inspire Record 1290358 DOI 10.17182/hepdata.64422
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First measurement of the forward-backward asymmetry in bottom-quark pair production at high mass

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev. D92 (2015) 032006, 2015.
Inspire Record 1364882 DOI 10.17182/hepdata.73682

We measure the particle-level forward-backward production asymmetry in bb¯ pairs with masses (mbb¯) larger than 150  GeV/c2, using events with hadronic jets and employing jet charge to distinguish b from b¯. The measurement uses 9.5  fb-1 of pp¯ collisions at a center-of-mass energy of 1.96 TeV recorded by the CDF II detector. The asymmetry as a function of mbb¯ is consistent with zero, as well as with the predictions of the standard model. The measurement disfavors a simple model including an axigluon with a mass of 200  GeV/c2, whereas a model containing a heavier 345  GeV/c2 axigluon is not excluded.

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Measurement of the forward-backward asymmetry in $Z/\gamma^{\ast} \rightarrow \mu^{+}\mu^{-}$ decays and determination of the effective weak mixing angle

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
JHEP 1511 (2015) 190, 2015.
Inspire Record 1394859 DOI 10.17182/hepdata.76490

The forward-backward charge asymmetry for the process $ q\overline{q}\to Z/{\gamma}^{\ast}\to {\mu}^{+}{\mu}^{-} $ is measured as a function of the invariant mass of the dimuon system. Measurements are performed using proton proton collision data collected with the LHCb detector at $ \sqrt{s}=7 $ and 8 TeV, corresponding to integrated luminosities of 1 fb$^{−1}$ and 2 fb$^{−1}$ respectively. Within the Standard Model the results constrain the effective electroweak mixing angle to be $ { \sin}^2{\theta}_{\mathrm{W}}^{\mathrm{eff}}=0.23142\pm 0.00073\pm 0.00052\pm 0.00056, $ where the first uncertainty is statistical, the second systematic and the third theoretical. This result is in agreement with the current world average, and is one of the most precise determinations at hadron colliders to date.

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Measurement of the forward–backward asymmetry of top-quark and antiquark pairs using the full CDF Run II data set

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev. D93 (2016) 112005, 2016.
Inspire Record 1424841 DOI 10.17182/hepdata.77054

We measure the forward–backward asymmetry of the production of top-quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy s=1.96  TeV using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of 9.1  fb-1. The asymmetry is characterized by the rapidity difference between top quarks and antiquarks (Δy) and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be AFBtt¯=0.12±0.13, consistent with the expectations from the standard model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive AFBtt¯ in both final states yields AFBtt¯=0.160±0.045, which is consistent with the SM predictions. We also measure the differential asymmetry as a function of Δy. A linear fit to AFBtt¯(|Δy|), assuming zero asymmetry at Δy=0, yields a slope of α=0.14±0.15, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of AFBtt¯(|Δy|) in the two final states is α=0.227±0.057, which is 2.0σ larger than the SM prediction.

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Measurement of the forward-backward asymmetry in low-mass bottom-quark pairs produced in proton-antiproton collisions

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev. D93 (2016) 112003, 2016.
Inspire Record 1416824 DOI 10.17182/hepdata.77045

We report a measurement of the forward-backward asymmetry, AFB, in bb¯ pairs produced in proton-antiproton collisions and identified by muons from semileptonic b-hadron decays. The event sample is collected at a center-of-mass energy of s=1.96  TeV with the CDF II detector and corresponds to 6.9  fb-1 of integrated luminosity. We obtain an integrated asymmetry of AFB(bb¯)=(1.2±0.7)% at the particle level for b-quark pairs with invariant mass, mbb¯, down to 40  GeV/c2 and measure the dependence of AFB(bb¯) on mbb¯. The results are compatible with expectations from the standard model.

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Measurement of the $W$ charge asymmetry in the $W \to \mu \nu$ decay mode in $pp$ collisions at $\sqrt s=7$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Lett. B701 (2011) 31-49, 2011.
Inspire Record 892704 DOI 10.17182/hepdata.85594

This letter reports a measurement of the muon charge asymmetry from W Boson produced in proton-proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS experiment at the LHC. The asymmetry is measured in the W Boson to muon decay mode as a function of the muon pseudorapidity using a data sample corresponding to a total integrated luminosity of 31 pb-1. The results are compared to predictions based on next-to-leading order calculations with various parton distribution functions. This measurement provides information on the u and d quark momentum fractions in the proton.

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Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at $\sqrt{s}=8\,\mathrm TeV{}$ with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J. C76 (2016) 87, 2016.
Inspire Record 1392455 DOI 10.17182/hepdata.75528

This paper reports inclusive and differential measurements of the $t\bar{t}$ charge asymmetry $A_{\text {C}}$ in $20.3~{\mathrm{fb}^{-1}}$ of $\sqrt{s} = 8~\mathrm TeV{}$ $pp$ collisions recorded by the ATLAS experiment at the Large Hadron Collider at CERN. Three differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the $t\bar{t}$ system. The $t\bar{t}$ pairs are selected in the single-lepton channels (e or $\mu $ ) with at least four jets, and a likelihood fit is used to reconstruct the $t\bar{t}$ event kinematics. A Bayesian unfolding procedure is performed to infer the asymmetry at parton level from the observed data distribution. The inclusive $t\bar{t}$ charge asymmetry is measured to be $A_{\text {C}}{} = 0.009 \pm 0.005$ (stat. $+$ syst.). The inclusive and differential measurements are compatible with the values predicted by the Standard Model.

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Measurement of the charge asymmetry in highly boosted top-quark pair production in $\sqrt{s} =$ 8 TeV $pp$ collision data collected by the ATLAS experiment

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Lett. B756 (2016) 52-71, 2016.
Inspire Record 1410588 DOI 10.17182/hepdata.77021

In the pp→tt¯ process the angular distributions of top and anti-top quarks are expected to present a subtle difference, which could be enhanced by processes not included in the Standard Model. This Letter presents a measurement of the charge asymmetry in events where the top-quark pair is produced with a large invariant mass. The analysis is performed on 20.3 fb −1 of pp collision data at s=8TeV collected by the ATLAS experiment at the LHC, using reconstruction techniques specifically designed for the decay topology of highly boosted top quarks. The charge asymmetry in a fiducial region with large invariant mass of the top-quark pair ( mtt¯>0.75 TeV ) and an absolute rapidity difference of the top and anti-top quark candidates within −2<|yt|−|yt¯|<2 is measured to be 4.2±3.2% , in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three tt¯ mass bins is also presented.

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Measurement of top quark polarisation in t-channel single top quark production

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 1604 (2016) 073, 2016.
Inspire Record 1403169 DOI 10.17182/hepdata.38092
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Measurement of the differential cross section and charge asymmetry for inclusive $\mathrm {p}\mathrm {p}\rightarrow \mathrm {W}^{\pm }+X$ production at ${\sqrt{s}} = 8$ TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J. C76 (2016) 469, 2016.
Inspire Record 1426517 DOI 10.17182/hepdata.73900
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Study of the production of $\Lambda_b^0$ and $\overline{B}^0$ hadrons in $pp$ collisions and first measurement of the $\Lambda_b^0\rightarrow J/\psi pK^-$ branching fraction

The LHCb collaboration Aaij, R. ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
Chin.Phys. C40 (2016) 011001, 2016.
Inspire Record 1391317 DOI 10.17182/hepdata.75485

The product of the differential production cross-section and the branching fraction of the decay is measured as a function of the beauty hadron transverse momentum, p(T), and rapidity, y. The kinematic region of the measurements is p(T) < 20 GeV/c and 2.0 < y < 4.5. The measurements use a data sample corresponding to an integrated luminosity of 3fb(−)(1) collected by the LHCb detector in pp collisions at centre-of-mass energies in 2011 and in 2012. Based on previous LHCb results of the fragmentation fraction ratio the branching fraction of the decay is measured to bewhere the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay B̅(0) → J/ψK̅*(892)(0), and the fourth is due to the knowledge of . The sum of the asymmetries in the production and decay between and is also measured as a function of p(T) and y. The previously published branching fraction of , relative to that of , is updated. The branching fractions of are determined.

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Angular analysis of the decay $B^0 \to K^{*0} \mu^+ \mu^-$ from pp collisions at $\sqrt s = 8$ TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett. B753 (2016) 424-448, 2016.
Inspire Record 1385600 DOI 10.17182/hepdata.17057
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Study of W boson production in pPb collisions at $\sqrt{s_{\mathrm{NN}}} =$ 5.02 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett. B750 (2015) 565-586, 2015.
Inspire Record 1353541 DOI 10.17182/hepdata.69232
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Indirect measurement of $\sin^2 \theta_W$ (or $M_W$) using $\mu^+\mu^-$ pairs from $\gamma^*/Z$ bosons produced in $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev. D89 (2014) 072005, 2014.
Inspire Record 1280719 DOI 10.17182/hepdata.64738

Drell-Yan lepton pairs are produced in the process $p\bar{p} \rightarrow \mu^+\mu^- + X$ through an intermediate $\gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $\mu^-$ as a function of the invariant mass of the $\mu^+\mu^-$ pair is used to obtain the effective leptonic determination $\sin^2 \theta^{lept}_{eff}$ of the electroweak-mixing parameter $\sin^2 \theta_W$, from which the value of $\sin^2 \theta_W$ is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2 fb-1 of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $\sin^2 \theta^{lept}_{eff}$ is found to be 0.2315 +- 0.0010, where statistical and systematic uncertainties are combined in quadrature. When interpreted within the context of the standard model using the on-shell renormalization scheme, where $\sin^2 \theta_W = 1 - M_W^2/M_Z^2$, the measurement yields $\sin^2 \theta_W$ = 0.2233 +- 0.0009, or equivalently a W-boson mass of 80.365 +- 0.047 GeV/c^2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider.

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Study of $W$ boson production in association with beauty and charm

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
Phys.Rev. D92 (2015) 052001, 2015.
Inspire Record 1370436 DOI 10.17182/hepdata.73718

The associated production of a W boson with a jet originating from either a light parton or heavy-flavor quark is studied in the forward region using proton-proton collisions. The analysis uses data corresponding to integrated luminosities of 1.0 and 2.0  fb-1 collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, respectively. The W bosons are reconstructed using the W→μν decay and muons with a transverse momentum, pT, larger than 20 GeV in the pseudorapidity range 2.0<η<4.5. The partons are reconstructed as jets with pT>20  GeV and 2.2<η<4.2. The sum of the muon and jet momenta must satisfy pT>20  GeV. The fraction of W+jet events that originate from beauty and charm quarks is measured, along with the charge asymmetries of the W+b and W+c production cross sections. The ratio of the W+jet to Z+jet production cross sections is also measured using the Z→μμ decay. All results are in agreement with Standard Model predictions.

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Measurement of $D_s^{\pm}$ production asymmetry in $pp$ collisions at $\sqrt{s} =7$ and 8 TeV

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
JHEP 1808 (2018) 008, 2018.
Inspire Record 1674916 DOI 10.17182/hepdata.82715

The inclusive D$_{s}^{±}$ production asymmetry is measured in pp collisions collected by the LHCb experiment at centre-of-mass energies of $ \sqrt{s}=7 $ and 8 TeV. Promptly produced D$_{s}^{±}$ mesons are used, which decay as D$_{s}^{±}$  → ϕπ$^{±}$, with ϕ → K$^{+}$K$^{−}$. The measurement is performed in bins of transverse momentum, p$_{T}$, and rapidity, y, covering the range 2.5 < p$_{T}$ < 25.0 GeV/c and 2.0 < y < 4.5. No kinematic dependence is observed. Evidence of nonzero D$_{s}^{±}$ production asymmetry is found with a significance of 3.3 standard deviations.

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