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

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
Phys.Rev.D 92 (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 $2.0\,{\rm fb}^{-1}$ collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, respectively. The $W$ bosons are reconstructed using the $W\to\mu\nu$ decay and muons with a transverse momentum, $p_{\rm T}$, larger than 20 GeV in the pseudorapidity range $2.0<\eta<4.5$. The partons are reconstructed as jets with $p_{\rm T} > 20$ GeV and $2.2 < \eta < 4.2$. The sum of the muon and jet momenta must satisfy $p_{\rm T} > 20$ 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 $Z\to\mu\mu$ decay. All results are in agreement with Standard Model predictions.

1 data table

Summary of the results. All results are reported within a fiducial region that requires a jet with $p_\rm{T} > 20$ GeV in the pseudorapidity range $2.2 < \eta < 4.2$, a muon with $p_\rm{T} > 20$ GeV in the pseudorapidity range $2.0 < \eta < 4.5$, $p_\rm{T}(\mu+j) > 20$ GeV, and $\Delta R(\mu, j) > 0.5$. For $Z+$jet events both muons must fulfill the muon requirements and $60 < M(\mu\mu) < 120$ GeV; the $Z+$jet fiducial region does not require $p_\rm{T}(\mu+j) > 20$ GeV.


Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ Decay Channels at $\sqrt{s}=8$ TeV with the ATLAS Detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.Lett. 115 (2015) 091801, 2015.
Inspire Record 1364361 DOI 10.17182/hepdata.57334

Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions.

17 data tables

Measured cross section in bins of $p_{\rm{T}}^{\rm{H}}$.

Measured cross section in bins of $|y^{\rm{H}}|$.

Measured cross section in bins of $N_{\rm{jets}}$.

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Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.D 92 (2015) 072004, 2015.
Inspire Record 1362183 DOI 10.17182/hepdata.68777

Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at $\sqrt{s}$ = 8 TeV corresponding to an integrated luminosity of 20.3 fb$^{-1}$ collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.

51 data tables

Vertex-level efficiency as a function of the vertex radial position for an RPV SUSY model of squark production with $\tilde{q}\to q[\tilde{\chi}_1^0\to\mu qq]$, where $m(\tilde{q}) = 700$ GeV, $m(\tilde{\chi}_1^0) = 494$ GeV and $c\tau(\tilde{\chi}_1^0)$ = 175 mm. This result is also represented in Figure 3b and Auxiliary Figure 1.

Vertex-level efficiency as a function of the vertex radial position for an RPV SUSY model of squark production with $\tilde{q}\to q[\tilde{\chi}_1^0\to\mu qq]$, where $m(\tilde{q}) = 700$ GeV, $m(\tilde{\chi}_1^0) = 108$ GeV and $c\tau(\tilde{\chi}_1^0)$ = 101 mm.

Vertex-level efficiency as a function of the vertex radial position for an RPV SUSY model of squark production with $\tilde{q}\to q[\tilde{\chi}_1^0\to\mu qb]$, where $m(\tilde{q}) = 700$ GeV, $m(\tilde{\chi}_1^0) = 494$ GeV and $c\tau(\tilde{\chi}_1^0)$ = 175 mm. The other SUSY model point in the figure is tabulated in http://hepdata.cedar.ac.uk/view/ins1362183/d1.

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Search for a pseudoscalar boson decaying into a Z boson and the 125 GeV Higgs boson in llbb final states

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 748 (2015) 221-243, 2015.
Inspire Record 1362177 DOI 10.17182/hepdata.70527

Results are reported on a search for decays of a pseudoscalar A boson into a Z boson and a light scalar h boson, where the Z boson decays into a pair of oppositely-charged electrons or muons, and the h boson decays into b anti-b. The search is based on data from proton-proton collisions at a center-of-mass energy sqrt(s)=8 TeV collected with the CMS detector, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The h boson is assumed to be the standard model-like Higgs boson with a mass of 125 GeV. With no evidence for signal, upper limits are obtained on the product of the production cross section and the branching fraction of the A boson in the Zh channel. Results are also interpreted in the context of two Higgs doublet models.

16 data tables

Observed and expected 95% CL upper limits on sigma A x B(A->Zh->llbb) as a function of mA in the narrow-width approximation, including statistical and systematic uncertainties.

Observed 95% CL upper limits on sigma A x B(A->Zh->llbb) as a function of mA and the A natural width Gamma.

Expected 95% CL upper limits on sigma A x B(A->Zh->llbb) as a function of mA and the A natural width Gamma.

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Analysis of events with $b$-jets and a pair of leptons of the same charge in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
JHEP 10 (2015) 150, 2015.
Inspire Record 1361912 DOI 10.17182/hepdata.67661

An analysis is presented of events containing jets including at least one $b$-tagged jet, sizeable missing transverse momentum, and at least two leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. A data sample with an integrated luminosity of 20.3 fb$^{-1}$ of $pp$ collisions at $\sqrt{s} = 8$ TeV recorded by the ATLAS detector at the Large Hadron Collider is used. Standard Model processes rarely produce these final states, but there are several models of physics beyond the Standard Model that predict an enhanced rate of production of such events; the ones considered here are production of vector-like quarks, enhanced four-top-quark production, pair production of chiral $b^\prime$-quarks, and production of two positively charged top quarks. Eleven signal regions are defined; subsets of these regions are combined when searching for each class of models. In the three signal regions primarily sensitive to positively charged top quark pair production, the data yield is consistent with the background expectation. There are more data events than expected from background in the set of eight signal regions defined for searching for vector-like quarks and chiral $b^\prime$-quarks, but the significance of the discrepancy is less than two standard deviations. The discrepancy reaches 2.5 standard deviations in the set of five signal regions defined for searching for four-top-quark production. The results are used to set 95% CL limits on various models.

10 data tables

Observed and expected number of events with statistical (first) and systematic (second) uncertainties for the positively charged top pair signal selection. The p-values for agreement between the observed yield and the expected background in each signal region are reported.

Observed and expected number of events with statistical (first) and systematic (second) uncertainties for five of the signal regions defined for VLQ, chiral bprime-quark and four-top-quark production searches. The p-values for agreement between the observed yield and the expected background in each signal region are reported.

Observed and expected number of events with statistical (first) and systematic (second) uncertainties for three of the signal regions defined for VLQ, chiral bprime-quark and four-top-quark production searches. The p-values for agreement between the observed yield and the expected background in each signal region are reported.

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Angular coefficients of Z bosons produced in pp collisions at $\sqrt{s}$ = 8 TeV and decaying to $\mu^+ \mu^-$ as a function of transverse momentum and rapidity

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 750 (2015) 154-175, 2015.
Inspire Record 1359451 DOI 10.17182/hepdata.69285

Measurements of the five most significant angular coefficients, A[0] through A[4], for Z bosons produced in pp collisions at $\sqrt{s}$ = 8 TeV and decaying to $\mu^+ \mu^-$ are presented as a function of the transverse momentum and rapidity of Z boson. The integrated luminosity of the dataset collected with the CMS detector at the LHC corresponds to 19.7 inverse femtobarns. These measurements provide comprehensive information about Z boson production mechanisms, and are compared to QCD predictions at leading order, next-to-leading order, and next-to-next-to-leading order in perturbation theory.

2 data tables

The five angular coefficients A0 to A4 and A0-A2 in bins of qT for |y| < 1.

The five angular coefficients A0 to A4 and A0-A2 in bins of qT for 1 < |y| < 2.1.


Measurement of the Z boson differential cross section in transverse momentum and rapidity in proton-proton collisions at 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 749 (2015) 187-209, 2015.
Inspire Record 1359450 DOI 10.17182/hepdata.68945

We present a measurement of the Z boson differential cross section in rapidity and transverse momentum using a data sample of pp collision events at a centre-of-mass energy sqrt(s)=8 TeV, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The Z boson is identified via its decay to a pair of muons. The measurement provides a precision test of quantum chromodynamics over a large region of phase space. In addition, due to the small experimental uncertainties in the measurement the data has the potential to constrain the gluon parton distribution function in the kinematic regime important for Higgs boson production via gluon fusion. The results agree with the next-to-next-to-leading-order predictions computed with the FEWZ program. The results are also compared to the commonly used leading-order MADGRAPH and next-to-leading-order POWHEG generators.

4 data tables

Measured double differential fiducial cross section normalised to the inclusive fiducial cross section. The uncertainty indicates the total experimental uncertainties (statistical and systematic added in quadrature).

Measured absolute double differential fiducial cross section. The uncertainty indicates the total experimental uncertainties (statistical and systematic added in quadrature).

Covariance matrix of total experimental uncertainties (statistical and systematic uncertainties added in quadrature) of double differential fiducial cross section normalised to the inclusive fiducial cross section. The bin index is PT_i + 10*y_j.

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Search for a Higgs boson in the mass range from 145 to 1000 GeV decaying to a pair of W or Z bosons

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 10 (2015) 144, 2015.
Inspire Record 1357982 DOI 10.17182/hepdata.70736

A search for a heavy Higgs boson in the H to WW and H to ZZ decay channels is reported. The search is based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at sqrt(s) = 7 TeV and up to 19.7 inverse femtobarns at sqrt(s) = 8 TeV, recorded by the CMS experiment at the CERN LHC. Several final states of the H to WW and H to ZZ decays are analyzed. The combined upper limit at the 95% confidence level on the product of the cross section and branching fraction exclude a Higgs boson with standard model-like couplings and decays in the range 145 < m[H] < 1000 GeV. We also interpret the results in the context of an electroweak singlet extension of the standard model.

5 data tables

Upper limits at 95\% CL on the cross section for a heavy Higgs boson decaying to a pair of W bosons as a function of its mass and its width relative to a SM-like Higgs boson.

Upper limits at 95\% CL on the cross section for a heavy Higgs boson decaying to a pair of Z bosons as a function of its mass and its width relative to a SM-like Higgs boson.

Upper limits at 95% CL on the cross section for a heavy Higgs boson as a function of its mass and its width relative to a SM-like Higgs boson. Both, gluon-gluon fusion and VBF production processes are combined, assuming a SM-like ratio between the two.

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Search for low-scale gravity signatures in multi-jet final states with the ATLAS detector at $\sqrt{s} = 8$ TeV

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
JHEP 07 (2015) 032, 2015.
Inspire Record 1357199 DOI 10.17182/hepdata.67127

We search for evidence of physics beyond the Standard Model in the production of final states with multiple high transverse momentum jets, using 20.3 fb$^{-1}$ of proton-proton collision data recorded by the ATLAS detector at $\sqrt{s} = 8$ TeV. No excess of events beyond Standard Model expectations is observed, and upper limits on the visible cross-section for non-Standard Model production of multi-jet final states are set. Using a wide variety of models for black hole and string ball production and decay, the limit on the cross-section times acceptance is as low as 0.16 fb at the 95% CL for a minimum scalar sum of jet transverse momentum in the event of about 4.3 TeV. Using models for black hole and string ball production and decay, exclusion contours are determined as a function of the production mass threshold and the gravity scale. These limits can be interpreted in terms of lower-mass limits on black hole and string ball production that range from 4.6 to 6.2 TeV.

13 data tables

Number of data events (20.3 fb$^{-1}$), number of predicted events from the fit, statistical uncertainty on the fit, systematic uncertainty on the choice of control region, and on the choice of fit function versus inclusive $H_{\textrm{T}}^{\textrm{min}}$ lower bin edge for inclusive jet multiplicity $N_{\textrm{Jet}} \geq 3$. The total uncertainty is obtained by adding the three uncertainties linearly.

Number of data events (20.3 fb$^{-1}$), number of predicted events from the fit, statistical uncertainty on the fit, systematic uncertainty on the choice of control region, and on the choice of fit function versus inclusive $H_{\textrm{T}}^{\textrm{min}}$ lower bin edge for inclusive jet multiplicity $N_{\textrm{Jet}} \geq 4$. The total uncertainty is obtained by adding the three uncertainties linearly.

Number of data events (20.3 fb$^{-1}$), number of predicted events from the fit, statistical uncertainty on the fit, systematic uncertainty on the choice of control region, and on the choice of fit function versus inclusive $H_{\textrm{T}}^{\textrm{min}}$ lower bin edge for inclusive jet multiplicity $N_{\textrm{Jet}} \geq 5$. The total uncertainty is obtained by adding the three uncertainties linearly.

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Evidence for Non-Exponential Elastic Proton-Proton Differential Cross-Section at Low |t| and sqrt(s) = 8 TeV by TOTEM

The TOTEM collaboration Antchev, G. ; Aspell, P. ; Atanassov, I. ; et al.
Nucl.Phys.B 899 (2015) 527-546, 2015.
Inspire Record 1356731 DOI 10.17182/hepdata.73431

The TOTEM experiment has made a precise measurement of the elastic proton-proton differential cross-section at the centre-of-mass energy sqrt(s) = 8 TeV based on a high-statistics data sample obtained with the beta* = 90 optics. Both the statistical and systematic uncertainties remain below 1%, except for the t-independent contribution from the overall normalisation. This unprecedented precision allows to exclude a purely exponential differential cross-section in the range of four-momentum transfer squared 0.027 < |t| < 0.2 GeV^2 with a significance greater than 7 sigma. Two extended parametrisations, with quadratic and cubic polynomials in the exponent, are shown to be well compatible with the data. Using them for the differential cross-section extrapolation to t = 0, and further applying the optical theorem, yields total cross-section estimates of (101.5 +- 2.1) mb and (101.9 +- 2.1) mb, respectively, in agreement with previous TOTEM measurements.

1 data table

The elastic differential cross-section as determined in this analysis using the ''optimised'' binning.