Measurements of t t-bar spin correlations and top quark polarization using dilepton final states in pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, V. ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 93 (2016) 052007, 2016.
Inspire Record 1413748 DOI 10.17182/hepdata.70879

Measurements of the top quark-antiquark (t t-bar) spin correlations and the top quark polarization are presented for t t-bar pairs produced in pp collisions at sqrt(s) = 8 TeV. The data correspond to an integrated luminosity of 19.5 inverse femtobarns collected with the CMS detector at the LHC. The measurements are performed using events with two oppositely charged leptons (electrons or muons) and two or more jets, where at least one of the jets is identified as originating from a bottom quark. The spin correlations and polarization are measured from the angular distributions of the two selected leptons, both inclusively and differentially, with respect to the invariant mass, rapidity, and transverse momentum of the t t-bar system. The measurements are unfolded to the parton level and found to be in agreement with predictions of the standard model. A search for new physics in the form of anomalous top quark chromo moments is performed. No evidence of new physics is observed, and exclusion limits on the real part of the chromo-magnetic dipole moment and the imaginary part of the chromo-electric dipole moment are evaluated.

106 data tables

Inclusive values of the asymmetry variables.

Values of the 12 bins of the normalized differential cross section as a function of $\left|\Delta \phi_{\ell^+\ell^-}\right|$.

Statistical covariance matrix for the 12 bins of the normalized differential cross section as a function of $\left|\Delta \phi_{\ell^+\ell^-}\right|$.

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Measurement of the WZ production cross section in pp collisions at sqrt{s} = 7 and 8 TeV and search for anomalous triple gauge couplings at sqrt{s} = 8 TeV

The CMS collaboration Khachatryan, V. ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J.C 77 (2017) 236, 2017.
Inspire Record 1487288 DOI 10.17182/hepdata.89400

The WZ production cross section is measured by the CMS experiment at the CERN LHC in proton-proton collision data samples corresponding to integrated luminosities of 4.9 inverse femtobarns collected at sqrt(s)= 7 TeV, and 19.6 inverse femtobarns at sqrt(s)= 8 TeV. The measurements are performed using the fully-leptonic WZ decay modes with electrons and muons in the final state. The measured cross sections for 71 < m[Z] < 111 GeV are sigma(pp to WZ; sqrt(s)= 7 TeV) = 20.14 +/- 1.32 (stat) +/- 1.13 (syst) +/- 0.44 (lumi) pb and sigma(pp to WZ; sqrt(s)= 8 TeV) = 24.09 +/- 0.87 (stat) +/- 1.62 (syst) +/- 0.63 (lumi) pb. Differential cross sections with respect to the Z boson pt, the leading jet pt, and the number of jets are obtained using the sqrt(s)= 8 TeV data. The results are consistent with standard model predictions and constraints on anomalous triple gauge couplings are obtained.

5 data tables

The measured WZ cross section for 71 < mZ < 111 GeV using 7 TeV data. The theory uncertainty only includes QCD scales variations.

The measured WZ cross section for 71 < mZ < 111 GeV using 8 TeV data. The theory uncertainty only includes QCD scales variations.

Differential cross section as function of the Z boson transverse momentum.

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Measurements of the associated production of a Z boson and b jets in pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, V. ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J.C 77 (2017) 751, 2017.
Inspire Record 1499471 DOI 10.17182/hepdata.77544

Measurements of the associated production of a Z boson with at least one jet originating from a b quark in proton-proton collisions at sqrt(s) = 8 TeV are presented. Differential cross sections are measured with data collected by the CMS experiment corresponding to an integrated luminosity of 19.8 inverse femtobarns. Z bosons are reconstructed through their decays to electrons and muons. Cross sections are measured as a function of observables characterizing the kinematics of the b jet and the Z boson. Ratios of differential cross sections for the associated production with at least one b jet to the associated production with any jet are also presented. The production of a Z boson with two b jets is investigated, and differential cross sections are measured for the dijet system. Results are compared to theoretical predictions, testing two different flavour schemes for the choice of initial-state partons.

20 data tables

Differential fiducial cross section for Z(1b) production as a function of the leading b jet pT

Cross section ratio for Z(1b) and Z+jets production as a function of the leading b/inclusive (j) jet pT

Differential fiducial cross section for Z(1b) production as a function of the leading b jet |eta|

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Search for light bosons in decays of the 125 GeV Higgs boson in proton-proton collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, V. ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 10 (2017) 076, 2017.
Inspire Record 1508173 DOI 10.17182/hepdata.81708

A search is presented for decays beyond the standard model of the 125 GeV Higgs bosons to a pair of light bosons, based on models with extended scalar sectors. Light boson masses between 5 and 62.5 GeV are probed in final states containing four tau leptons, two muons and two b quarks, or two muons and two tau leptons. The results are from data in proton-proton collisions corresponding to an integrated luminosity of 19.7 inverse femtobarns, accumulated by the CMS experiment at the LHC at a center-of-mass energy of 8 TeV. No evidence for such exotic decays is found in the data. Upper limits are set on the product of the cross section and branching fraction for several signal processes. The results are also compared to predictions of two-Higgs-doublet models, including those with an additional scalar singlet.

6 data tables

Median expected 95% CL limits on the branching fraction B(h-->aa)*B^2(a-->tautau) assuming SM h production rates for pseudoscalar mass points between 5 and 15 GeV.

Median observed 95% CL limits on the branching fraction B(h-->aa)*B^2(a-->tautau) assuming SM h production rates for pseudoscalar mass points between 5 and 15 GeV.

Median expected 95% CL limits on the branching fraction B(h-->aa)*B(a-->mumu)*B(a-->bb) assuming SM h production rates for pseudoscalar mass points between 25 and 62.5 GeV.

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Measurement of $W^+ W^-$ and $ZZ$ Production Cross Sections in $pp$ Collisions at $\sqrt{s} = 8 TeV$

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Lett.B 721 (2013) 190-211, 2013.
Inspire Record 1215317 DOI 10.17182/hepdata.62680

The W+W- and ZZ production cross sections are measured in proton-proton collisions at sqrt(s) = 8 TeV with the CMS experiment at the LHC in data samples corresponding to an integrated luminosity of up to 5.3 inverse femtobarns. The measurements are performed in the leptonic decay modes W+W- to l' nu l'' nu and ZZ to 2l 2l', where l = e, mu and l'(l'') = e, mu, tau. The measured cross sections sigma(pp to W+W-) = 69.9 +/- 2.8 (stat.) +/- 5.6 (syst.) +/- 3.1 (lumi.) pb and sigma(pp to ZZ) = 8.4 +/- 1.0 (stat.) +/- 0.7 (syst.) +/- 0.4 (lumi.) pb, for both Z bosons produced in the mass region 60 < m[Z] < 120 GeV, are consistent with standard model predictions. These are the first measurements of the diboson production cross sections at sqrt(s) = 8 TeV.

2 data tables

The measured cross section for W+ W- production performed in the W --> LEPTONPRIME NU mode where LEPTONPRIME is electron, muon or tau.

The measured cross section for Z0Z0 production performed in the Z0 --> LEPTON LEPTONPRIME mode where LEPTON is E or MU and LEPTONPRIME is E, MU or TAU.


Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at sqrt(s)= 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 08 (2014) 173, 2014.
Inspire Record 1294937 DOI 10.17182/hepdata.2348

A search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of multijet events corresponding to an integrated luminosity of 19.7 inverse femtobarns, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. The search uses novel jet-substructure identification techniques that provide sensitivity to the presence of highly boosted vector bosons decaying into a pair of quarks. Exclusion limits are set at a confidence level of 95% on the production of: (i) excited quark resonances q* decaying to qW and qZ for masses less than 3.2 TeV and 2.9 TeV, respectively, (ii) a Randall-Sundrum graviton G[RS] decaying into WW for masses below 1.2 TeV, and (iii) a heavy partner of the W boson W' decaying into WZ for masses less than 1.7 TeV. For the first time mass limits are set on W' to WZ and G[RS] to WW in the all-jets final state. The mass limits on q* to qW, q* to qZ, W' to WZ, G[RS] to WW are the most stringent to date. A model with a "bulk" graviton G[Bulk] that decays into WW or ZZ bosons is also studied.

9 data tables

DATA - Double W/Z tagged events in HIGH purity bin.

BACKGROUND - Double W/Z tagged background in HIGH purity bin estimated from a fit to data.

BACKGROUND PLUS - Double W/Z tagged background variation upward (1 sigma) in HIGH purity bin estimated from a fit to data.

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Search for heavy neutrinos and W[R] bosons with right-handed couplings in a left-right symmetric model 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) 261802, 2012.
Inspire Record 1189986 DOI 10.17182/hepdata.21263

Results are presented from a search for heavy, right-handed muon neutrinos, N[mu], and right-handed W[R] bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5.0 inverse femtobarn sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron Collider. No evidence is observed for an excess of events over the standard model expectation. For models with exact left-right symmetry, heavy right-handed neutrinos are excluded at 95% confidence level for a range of neutrino masses below the W[R] mass, dependent on the value of M(W[R]). The excluded region in the two-dimensional (M(W[R]), M(N[mu])) mass plane extends to M(W[R]) = 2.5 TeV.

1 data table

The 95% confidence level observed (Obs.) and expected (Exp.) exclusion limits (in fb) on the WR production cross section times branching fraction for WR -> mu mu j j as a function of WR (mWR) and Nmu (mNmu) mass (in GeV) for 800 GeV <= mWR <= 2500 GeV. The 68% and 95% uncertainty bands for the expected limit (Exp. 68% up/down and Exp. 95% up/down, respectively), given in fb, are also included for each (mWR,mNmu) entry.


Measurement of the ratio B(Bc+/- to J/psi pi+/- pi+/- pi-/+)/B(Bc+/- to J/psi pi+/-) and the production cross sections times branching fractions of Bc+/- to J/psi pi+/- and B+/- to J/psi K+/- in pp collisions at sqrt(s) = 7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 01 (2015) 063, 2015.
Inspire Record 1323075 DOI 10.17182/hepdata.39386

The ratio of the production cross sections times branching fractions (sigma(Bc+) B(Bc+ to J/psi pi+))/ (sigma(B+) B(B+ to J/psi K+)) is studied in proton-proton collisions at a center-of-mass energy of 7 TeV with the CMS detector at the LHC. The kinematic region investigated requires Bc+/- and B+/- mesons with transverse momentum pt > 15 GeV and rapidity abs(y) < 1.6. The data sample corresponds to an integrated luminosity of 5.1 inverse femtobarns. The ratio is determined to be [0.48 +/- 0.05 (stat) +/- 0.03 (syst) +/- 0.05 (tau_{Bc})]% The J/psi pi+/- pi+/- pi-/+ decay mode is also observed in the same data sample. Using a model-independent method developed to measure the efficiency given the presence of resonant behaviour in the three-pion system, the ratio of the branching fractions B(Bc+/- to J/psi pi+/- pi+/- pi-/+) / B(Bc+/- to J/psi pi+/-) is measured to be 2.55 +/- 0.80 (stat) +/- 0.33 (syst) +0.04/-0.01 (tau[Bc+]), consistent with the previous LHCb result.

2 data tables

The ratio of the production cross sections times branching fractions of $B_c^\pm\to J/\psi\pi^\pm$ and $B^\pm\to J/\psi K^\pm$ is measured in the kinematic region $p_T$> 15 GeV and |y| < 1.6. Beside the statistical and systematic errors, an uncertainty associated to the $B_c^{\pm}$ lifetime is quoted as a separate third error. The $B_c^\pm\to J/\psi\pi^\pm$ reconstruction efficiency has a dependence on the $B_c^\pm$ lifetime. Recently LHCb published a more precise $B_c^\pm$ lifetime measurement, which is significantly higher than the previous world average (PDG 2012). To determine the systematic uncertainty associated with the uncertainty in the $B_c^\pm$ lifetime, the efficiency is evaluated while changing the $B_c^\pm$ lifetime in the simulation to cover the range from the world average minus its one standard deviation uncertainty, to the new LHCb measurement. The resulting variation in the ratio is quoted separately as a lifetime systematic uncertainty ($\tau_{Bc}$). Charge conjugation is implied in the table.

To determine the systematic uncertainty in the ratio of branching fractions associated with the uncertainty in the $B_c^\pm$ lifetime, the efficiency is evaluated while changing the $B_c^\pm$ lifetime in the simulation to cover the range from the world average minus its one standard deviation uncertainty, to the new LHCb measurement. The resulting variation in the ratio is quoted separately as a lifetime systematic uncertainty ($\tau_{Bc}$). Charge conjugation is implied in the table.


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 04 (2016) 073, 2016.
Inspire Record 1403169 DOI 10.17182/hepdata.38092

A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 inverse-femtobarns. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. A differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26 +/- 0.03 (stat) +/- 0.10 (syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.

4 data tables

The normalized differential cross section as a function of unfolded $\cos\theta_{\mu}^{*}$ for top quark.

The normalized differential cross section as a function of unfolded $\cos\theta_{\mu}^{*}$ for top antiquark.

The normalized differential cross section as a function of unfolded $\cos\theta_{\mu}^{*}$ for top quark and antiquark.

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Angular analysis of the decay B0 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.B 753 (2016) 424-448, 2016.
Inspire Record 1385600 DOI 10.17182/hepdata.17057

The angular distributions and the differential branching fraction of the decay B0 to K*0(892) mu mu are studied using data corresponding to an integrated luminosity of 20.5 inverse femtobarns collected with the CMS detector at the LHC in pp collisions at sqrt(s) = 8 TeV. From 1430 signal decays, the forward-backward asymmetry of the muons, the K*0(892) longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions.

2 data tables

The measured values of signal yield, FL, AFB, and differential branching fraction in bins of the dimuon invariant mass squared. The (FL,AFB) correlation factors are also shown.

The measured values of FL, AFB, and differential branching fraction in bins of the dimuon invariant mass squared, combining the 7 TeV and 8 TeV results.