| 1. |
- Aaltonen, T., et al.
(author)
-
Combination of CDF and D0 W-Boson mass measurements
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052018-
-
Journal article (peer-reviewed)abstract
- We summarize and combine direct measurements of the mass of the W boson in root s = 1.96 TeV proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to 2.2 fb(-1) of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to 4.3 fb(-1) of integrated luminosity. The resulting Tevatron average for the mass of the W boson is M-W = 80387 +/- 16 MeV. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of M-W = 80385 +/- 15 MeV.
|
|
| 2. |
- Aaltonen, T., et al.
(author)
-
Higgs boson studies at the Tevatron
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052014-
-
Journal article (peer-reviewed)abstract
- We combine searches by the CDF and D0 Collaborations for the standard model Higgs boson with mass in the range 90-200 GeV/c(2) produced in the gluon-gluon fusion, WH, ZH, t (t) over barH, and vector boson fusion processes, and decaying in the H -> b (b) over bar, H -> W+W-, H -> ZZ, H -> tau(+)tau(-), and H -> gamma gamma modes. The data correspond to integrated luminosities of up to 10 fb(-1) and were collected at the Fermilab Tevatron in p (p) over bar collisions at root s = 1.96 TeV. The searches are also interpreted in the context of fermiophobic and fourth generation models. We observe a significant excess of events in the mass range between 115 and 140 GeV/c(2). The local significance corresponds to 3.0 standard deviations at m(H) = 125 GeV/c(2), consistent with the mass of the Higgs boson observed at the LHC, and we expect a local significance of 1.9 standard deviations. We separately combine searches for H -> b (b) over bar, H -> W+W-, H -> tau(+)tau(-), and H -> gamma gamma. The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 125 GeV/c(2).
|
|
| 3. |
- Abazov, V. M., et al.
(author)
-
Measurement of direct CP violation parameters in B-+/- -> J/psi K-+/- and B-+/- -> J/psi pi(+/-) decays with 10.4 fb(-1) of Tevatron data
- 2013
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 110:24, s. 241801-
-
Journal article (peer-reviewed)abstract
- We present a measurement of the direct CP-violating charge asymmetry in B-+/- mesons decaying to J/psi K-+/- and J/psi pi(+/-) where J/psi decays to mu(+)mu(-), using the full run II data set of 10.4 fb(-1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. A difference in the yield of B- and B+ mesons in these decays is found by fitting to the difference between their reconstructed invariant mass distributions resulting in asymmetries of A(J/psi K) = [0.59 +/- 0.37]%, which is the most precise measurement to date, and A(J/psi pi) = [-4.2 +/- 4.5]%. Both measurements are consistent with standard model predictions.
|
|
| 4. |
- Abazov, V. M., et al.
(author)
-
Combined search for the Higgs boson with the D0 experiment
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052011-
-
Journal article (peer-reviewed)abstract
- We perform a combination of searches for standard model Higgs boson production in p (p) over bar collisions recorded by the D0 detector at the Fermilab Tevatron Collider at a center of mass energy of root s = 1.96 TeV. The different production and decay channels have been analyzed separately, with integrated luminosities of up to 9.7 fb(-1) and for Higgs boson masses 90 <= M-H <= 200 GeV. We combine these final states to achieve optimal sensitivity to the production of the Higgs boson. We also interpret the combination in terms of models with a fourth generation of fermions, and models with suppressed Higgs boson couplings to fermions. The result excludes a standard model Higgs boson at 95% C.L. in the ranges 90 < M-H < 101 GeV and 157 < M-H < 178 GeV, with an expected exclusion of 155 < M-H < 175 GeV. In the range 120 < M-H < 145 GeV, the data exhibit an excess over the expected background of up to 2 standard deviations, consistent with the presence of a standard model Higgs boson of mass 125 GeV.
|
|
| 5. |
- Abazov, V. M., et al.
(author)
-
Evidence for s-channel single top quark production in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 726:4-5, s. 656-664
-
Journal article (peer-reviewed)abstract
- We present measurements of the cross sections for the two main production modes of single top quarks in p (p) over bar collisions at root s = 1.96 TeV in the Run II data collected with the DO detector at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.7 fb(-1). The s-channel cross section is measured to be sigma(p (p) over bar -> tb + X) = 1.10(-0.31)(+0.33) pb with no assumptions on the value of the t-channel cross section. Similarly, the t-channel cross section is measured to be sigma(p (p) over bar -> tqb + X) = 3.07(-0.49)(+0.54) pb. We also measure the s + t combined cross section as sigma(p (p) over bar -> tb + X, tqb + X) = 4.11(-0.55)(+0.60) ph and set a lower limit on the CKM matrix element vertical bar V-tb vertical bar> 0.92 at 95% C.L., assuming mt = 172.5 GeV. The probability to measure a cross section for the s channel at the observed value or higher in the absence of signal is 1.0 x 10(-4), corresponding to a significance of 3.7 standard deviations.
|
|
| 6. |
- Abazov, V. M., et al.
(author)
-
Measurement of leptonic asymmetries and top-quark polarization in t(t)over-bar production
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:1, s. 011103-
-
Journal article (peer-reviewed)abstract
- We present measurements of lepton (l) angular distributions in top-quark (t) pair production and t (t) over bar -> W(+)bW-(b) over bar -> l(+) vbl-(v) over bar(b) over bar decays produced in p (p) over bar collisions at a center-of-mass energy of root s = 1.96 TeV, where l is an electron or muon. Using data corresponding to an integrated luminosity of 5.4 fb(-1), collected with the D0 detector at the Fermilab Tevatron Collider, we measure for the first time the leptonic forward-backward asymmetry in dilepton final states and obtain A(FB)(l) = (5.8 +/- 5.1(stat) +/- 1.3(syst))%, corrected for detector acceptance. This is compared to the standard model prediction of A(FB)(l)(predicted) = (4.7 +/- 0.1)%. A deviation from the standard model prediction as previously seen in a D0 measurement based on the analysis of the l + jets final state is not observed in these dilepton final states. The two results differ from each other by 1.4 standard deviations and are combined to obtain A(FB)(l) = (11.8 +/- 3.2)%. Furthermore, we present a first study of the top-quark polarization.
|
|
| 7. |
- Abazov, V. M., et al.
(author)
-
Measurement of the asymmetry in angular distributions of leptons produced in dilepton t(t)over-bar final states in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:11, s. 112002-
-
Journal article (peer-reviewed)abstract
- We present measurements of asymmetries in angular distributions of leptons produced in t (t) over bar events in proton-antiproton collisions at the Fermilab Tevatron Collider. We consider final states where the W-+/- bosons from top quark and antiquark decays both decay into l nu (l = e, mu) resulting in oppositely charged dilepton final states with accompanying jets. Using 9.7 fb(-1) of integrated luminosity collected with the D0 detector, we find the asymmetries in lepton pseudorapidity compatible with predictions based on the standard model.
|
|
| 8. |
- Abazov, V. M., et al.
(author)
-
Measurement of the combined rapidity and p(T) dependence of dijet azimuthal decorrelations in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 721:4-5, s. 212-219
-
Journal article (peer-reviewed)abstract
- We present the first combined measurement of the rapidity and transverse momentum dependence of dijet azimuthal decorrelations, using the recently proposed quantity R-Delta phi. The variable R-Delta phi measures the fraction of the inclusive dijet events in which the azimuthal separation of the two jets with the highest transverse momenta is less than a specified value of the parameter Delta phi(max). The quantity R-Delta phi is measured in p (p) over bar collisions at root s = 1.96 TeV, as a function of the dijet rapidity interval, the total scalar transverse momentum, and Delta phi(max). The measurement uses an event sample corresponding to an integrated luminosity of 0.7 fb(-1) collected with the DO detector at the Fermilab Tevatron Collider. The results are compared to predictions of a perturbative QCD calculation at next-to-leading order in the strong coupling with corrections for non-perturbative effects. The theory predictions describe the data well, except in the kinematic region of large dijet rapidity intervals and small Delta phi(max).
|
|
| 9. |
- Abazov, V. M., et al.
(author)
-
Measurement of the differential cross section of photon plus jet production in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:7, s. 072008-
-
Journal article (peer-reviewed)abstract
- We study the process of associated photon and jet production, p (p) over bar -> gamma + jet + X, using 8.7 fb(-1) of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy root s = 1.96 TeV. Photons are reconstructed with rapidity vertical bar y(gamma)vertical bar < 1.0 or 1.5 < vertical bar y(gamma)vertical bar < 2.5 and transverse momentum p(T)(gamma) > 20 GeV. The highest-p(T) jet is required to be in one of four rapidity regions up to vertical bar y(jet)vertical bar <= 3.2. For each rapidity configuration we measure the differential cross sections in p(T)(gamma) separately for events with the same sign (y(gamma)y(jet) > 0) and opposite signs (y(gamma)y(jet) <= 0) of photon and jet rapidities. We compare the measured triple-differential cross sections, d(3)sigma/dp(T)(gamma)dy(gamma)dy(jet), to next-to-leading order (NLO) perturbative QCD calculations using different sets of parton distribution functions, and to predictions from the SHERPA and PYTHIA Monte Carlo event generators. The NLO calculations are found to be in general agreement with the data but do not describe all kinematic regions.
|
|
| 10. |
- Abazov, V. M., et al.
(author)
-
Measurement of the differential cross sections for isolated direct photon pair production in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 725:1-3, s. 6-14
-
Journal article (peer-reviewed)abstract
- We present measurements of direct photon pair production cross sections using 8.5 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron p (p) over bar collider. The results are presented as differential distributions of the photon pair invariant mass d sigma/dM(gamma gamma), pair transverse momentum d sigma/dp(T)(gamma gamma) azimuthal angle between the photons d sigma/d Delta(phi)(gamma gamma), and polar scattering angle in the Collins-Soper frame d sigma/d vertical bar cos theta*vertical bar. Measurements are performed for isolated photons with transverse momenta p(T)(gamma) > 18 (17) GeV for the leading (next-to-leading) photon in P-T, pseudorapidities vertical bar eta(gamma)vertical bar < 0.9, and a separation in eta-phi space Delta R-gamma gamma > 0.4. We present comparisons with the predictions from Monte Carlo event generators DIPHOX and RESBOS implementing QCD calculations at next-to-leading order, 2 gamma NNLO at next-to-next-to-leading order, and SHERPA using matrix elements with higher-order real emissions matched to parton shower.
|
|
| 11. |
- Abazov, V. M., et al.
(author)
-
Measurement of the differential gamma plus c-jet cross section and the ratio of differential gamma plus c and gamma plus b cross sections in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 719:4-5, s. 354-361
-
Journal article (peer-reviewed)abstract
- We present measurements of the differential cross section d sigma/dp(T)(gamma) for the associated production of a c-quark jet and an isolated photon with rapidity vertical bar y(gamma)vertical bar < 1.0 and transverse momentum 30 < p(T)(gamma) < 300 GeV. The c-quark jets are required to have vertical bar y(jet)vertical bar < 1.5 and p(T)(jet) > 15 GeV. The ratio of differential cross sections for gamma + c to gamma + b production as a function of p(T)(gamma) is also presented. The results are based on data corresponding to an integrated luminosity of 8.7 fb(-1) recorded with the D0 detector at the Fermilab Tevatron p (p) over bar Collider at root s = 1.96 TeV. The obtained results are compared to next-to-leading order perturbative QCD calculations using various parton distribution functions, to predictions based on the k(T)-factorization approach, and to predictions from the SHERPA and PYTHIA Monte Carlo event generators.
|
|
| 12. |
- Abazov, V. M., et al.
(author)
-
Measurement of the muon charge asymmetry in p(p)over-bar -> W + X -> mu nu + X events at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:9, s. 091102-
-
Journal article (peer-reviewed)abstract
- We present a measurement of the muon charge asymmetry from the decay of the W boson via W -> mu nu using 7: 3 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. The muon charge asymmetry is presented in two kinematic regions in muon transverse momentum and event missing transverse energy: (p(T)(mu) > 25 GeV, E-T > 25 GeV) and (p(T)(mu) > 35 GeV, E-T > 35 GeV). The measured asymmetries are compared with theory predictions made using three parton distribution function sets. The data at p(T)(mu) > 35 GeV, E-T > 35 GeV, and larger values of vertical bar eta(mu)vertical bar favor an increased d(x)/u(x) ratio at higher values of x than is predicted.
|
|
| 13. |
- Abazov, V. M., et al.
(author)
-
Measurement of the p(p)over-bar -> W plus b plus X production cross section at root s=1.96 TeV D0 Collaboration
- 2013
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 718:4-5, s. 1314-1320
-
Journal article (peer-reviewed)abstract
- We present a measurement of the cross section for W boson production in association with at least one b-quark jet in proton-antiproton collisions. The measurement is made using data corresponding to an integrated luminosity of 6.1fb-1 recorded with the D0 detector at the Fermilab Tevatron pp̄ Collider at s=1.96TeV. We measure an inclusive cross section of σ(W(→μν)+b+X)=1.04±0.05(stat.)±0.12(syst.) pb and σ(W(→eν)+b+X)=1.00±0.04(stat.)±0.12(syst.) pb in the phase space defined by pTν>25GeV, pTb-jet>20 GeV, |ηb-jet|<1.1, and a muon (electron) with pTℓ>20 GeV and |ημ|<1.7 (|ηe|<1.1 or 1.5<|ηe|<2.5). The combined result per lepton family is σ(W(→ℓν)+b+X)=1.05±0.12(stat.+syst.) pb for |ηℓ|<1.7. The results are in agreement with predictions from next-to-leading order QCD calculations using mcfm, σ(W+b){dot operator}B(W→ℓν)=1.34-0.34+0.41(syst.) pb, and also with predictions from the sherpa and madgraph Monte Carlo event generators.
|
|
| 14. |
- Abazov, V. M., et al.
(author)
-
Measurement of the ratio of differential cross sections sigma(p(p)over-bar -> Z + b jet)/sigma(p(p)over-bar -> Z + jet) in p(p)over-bar collisions at root s = 1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:9, s. 092010-
-
Journal article (peer-reviewed)abstract
- We measure the ratio of cross sections, sigma(p (p) over bar -> Z + b jet)/sigma(p (p) over bar -> Z + jet), for associated production of a Z boson with at least one jet. The ratio is also measured as a function of the Z boson transverse momentum, jet transverse momentum, jet pseudorapidity, and the azimuthal angle between the Z boson with respect to the highest p(T) b tagged jet. These measurements use data collected by the D0 experiment in Run II of Fermilab's Tevatron p (p) over bar Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of 9.7 fb(-1). The results are compared to predictions from next-to-leading order calculations and various Monte Carlo event generators.
|
|
| 15. |
- Abazov, V. M., et al.
(author)
-
Measurement of the ratio of three-jet to two-jet cross sections in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 720:1-3, s. 6-12
-
Journal article (peer-reviewed)abstract
- We present a measurement of the ratio of multijet cross sections in p (p) over barp collisions at root s = 1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a data set corresponding to an integrated luminosity of 0.7 fb(-1) collected with the DO detector. The ratio of the inclusive three-jet to two-jet cross sections, R-3/2, has been measured as a function of the jet transverse momenta. The data are compared to QCD predictions in different approximations. Popular tunes of the PYriiiA event generator do not agree with the data, while SHERPA provides a reasonable description of the data. A perturbative QCD prediction in next-to-leading order in the strong coupling constant, corrected for non-perturbative effects, gives a good description of the data.
|
|
| 16. |
- Abazov, V. M., et al.
(author)
-
Measurement of the Semileptonic Charge Asymmetry using B-S(0) -> D-s mu X Decays
- 2013
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 110:1, s. 011801-
-
Journal article (peer-reviewed)abstract
- We present a measurement of the time-integrated flavor-specific semileptonic charge asymmetry in the decays of B-s(0) mesons that have undergone flavor mixing, a(sl)(s), using B-s(0)((B) over bar (0)(s)) -> D-s(-/+) mu(+/-) X decays, with D-s(-/+) -> phi pi(-/+) and phi -> K+K-, using 10.4 fb(-1) of proton-antiproton collisions collected by the D0 detector during Run II at the Fermilab Tevatron Collider. A fit to the difference between the time-integrated D0 detector during Run II at the Fermilab Tevatron Colllider. A fit to the difference between the time-integrated D-s(-) and D-s(+) mass distributions of the B-s(0) and ($) over bar (0)(s) candidates yields the flavor-specific asymmetry a(sl)(s) = [-1.12 +/- 0.74(stat) +/- 0.17(syst)]%, which is the most precise measurement and in agreement with the standard model prediction.
|
|
| 17. |
- Abazov, V. M., et al.
(author)
-
Measurement of the ZZ production cross section and search for the standard model Higgs boson in the four lepton final state in p(p)over-bar collisions
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:3, s. 032008-
-
Journal article (peer-reviewed)abstract
- We present a measurement of Z boson pair production in p (p) over bar collisions at 1.96 TeV with 9.6 to 9.8 fb(-1) of D0 data. We examine the final states eeee, ee mu mu, and mu mu mu mu. Based on selected data, the measured cross section in the mass region M(Z/gamma*) > 30 GeV is sigma(p (p) over bar -> Z/gamma*Z/gamma*) = 1.26(-0.36)(+0.44)(stat)(-0.15)(+0.17) X (syst) +/- 0.08 (lumi) pb; after correcting for the expected ratio of sigma (p (p) over bar -> Z/gamma*Z/gamma*) to sigma(p (p) over bar -> ZZ), we derive a cross section for p (p) over bar -> ZZ production of 1.05(-0.30)(+0.37)(stat)(-0.12)(0.14)(syst) +/- 0.06 (lumi) pb. This result is combined with a previous result from the ZZ -> l(+)l(-) nu(nu) over bar channel resulting in a combined p (p) over bar -> ZZ cross section measurement of 1.32(-0.25)(+0.29) (stat) +/- 0.12 (syst) +/- 0.04 (lumi) pb. These measurements are consistent with the standard model expectation of 1.43 +/- 0.10 pb. We extend this analysis to search for the standard model (SM) Higgs boson between 115 and 200 GeV. At a Higgs boson mass of 125 GeV, we expect to set a limit of 43 times the SM expectation at 95% C.L., and set a limit of 42 times the SM expectation at 95% C.L.
|
|
| 18. |
- Abazov, V. M., et al.
(author)
-
Search for a Higgs boson in diphoton final states with the D0 detector in 9.6 fb(-1) of p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052007-
-
Journal article (peer-reviewed)abstract
- We present a search for a Higgs boson decaying into a pair of photons based on 9.6 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The search employs multivariate techniques to discriminate signal from the nonresonant background and is separately optimized for a standard model and a fermiophobic Higgs boson. No significant excess of data above the background prediction is observed and upper limits on the product of the cross section and branching fraction are derived at the 95% confidence level as a function of Higgs boson mass. For a standard model Higgs boson with mass of 125 GeV, the observed (expected) upper limits are a factor of 12.8 (8.7) above the standard model prediction. The existence of a fermiophobic Higgs boson with mass in the 100-113 GeV range is excluded at the 95% confidence level.
|
|
| 19. |
- Abazov, V. M., et al.
(author)
-
Search for anomalous quartic WW gamma gamma couplings in dielectron and missing energy final states in p(p)over-bar collisions at root s 1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:1, s. 012005-
-
Journal article (peer-reviewed)abstract
- We present a search for anomalous components of the quartic gauge boson coupling WW gamma gamma in events with an electron, a positron and missing transverse energy. The analyzed data correspond to 9.7 fb(-1) of integrated luminosity collected by the D0 detector in p (p) over bar collisions at root s 1.96 TeV. The presence of anomalous quartic gauge couplings would manifest itself as an excess of boosted WW events. No such excess is found in the data, and we set the most stringent limits to date on the anomalous coupling parameters a(0)(W) and a(C)(W). When a form factor with Lambda(cutoff) = 0.5 TeV is used, the observed upper limits at 95% C. L. are vertical bar a(0)(W)/Lambda(2)vertical bar < 0.0025 GeV-2 and vertical bar a(C)(W)/Lambda(2)vertical bar < 0.0092 GeV-2.
|
|
| 20. |
- Abazov, V. M., et al.
(author)
-
Search for charged massive long-lived particles at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:5, s. 052011-
-
Journal article (peer-reviewed)abstract
- We present a search for charged massive long-lived particles (CMLLPs) that are pair produced in p (p) over bar collisions at root s = 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron collider. Our result is a combination of two searches where either one or both CMLLPs are reconstructed in the detector. We select events with muonlike particles that have both speed and ionization energy loss (dE/dx) different from muons produced in p (p) over bar collisions. In the absence of evidence for CMLLPs corresponding to 6.3 fb(-1) of integrated luminosity, we set limits on the CMLLP masses in several supersymmetric models, excluding masses below 278 GeV for long-lived gaugino-like charginos, and masses below 244 GeV for long-lived Higgsino-like charginos at the 95% C.L. We also set limits on the cross section for pair production of long-lived scalar tau leptons that range from 0.04 to 0.008 pb for scalar tau lepton masses of 100-300 GeV.
|
|
| 21. |
- Abazov, V. M., et al.
(author)
-
Search for Higgs boson production in oppositely charged dilepton and missing energy final states in 9.7 fb(-1) of p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052006-
-
Journal article (peer-reviewed)abstract
- We present a search for the Higgs boson in final states with two oppositely charged leptons and large missing transverse energy as expected in H -> WW -> lvl(1)v(1)decays. The events are selected from the full Run II data sample of 9.7 fb(-1) of p (p) over bar collisions collected with the D0 detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. To validate our search methodology, we measure the nonresonant WW production cross section and find sigma(WW) 11.6 +/- 0.7 pb, in agreement with the standard model prediction. In the Higgs boson search, no significant excess above the background expectation is observed. Upper limits at the 95% confidence level on the Higgs boson production cross section are therefore derived. Within the standard model, the Higgs boson mass range 159 < M-H < 176 GeV is excluded while the expected exclusion sensitivity is 156 < M-H < 172 GeV. For a mass hypothesis of M-H = 125 GeV, we exclude Higgs boson production cross sections 4.1 times larger than the standard model expectation, which is compatible with the presence of a Higgs boson at this mass. Within a theoretical framework with a fourth generation of fermions, the mass range 125 < M-H < 218 GeV is excluded. The search results are also interpreted in the context of fermiophobic Higgs boson couplings, which yields an exclusion of fermiophobic Higgs boson production cross sections 3.1 times larger than the expectation for M-H = 125 GeV.
|
|
| 22. |
- Abazov, V. M., et al.
(author)
-
Search for Higgs boson production in trilepton and like-charge electron-muon final states with the D0 detector
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052009-
-
Journal article (peer-reviewed)abstract
- We present a search for Higgs bosons in multilepton final states in p (p) over bar collisions at root s = 1.96 TeV recorded with the D0 detector at the Fermilab Tevatron Collider, using the full Run II data set with integrated luminosities of up to 9.7 fb(-1). The multilepton states considered are ee mu, e mu mu, mu tau(h)tau(h) , and like-charge e(+/-) mu(+/-) pairs. These channels directly probe the HVV (V = W, Z) coupling of the Higgs boson in production and decay. The mu tau(h)tau(h) channel is also sensitive to H -> tau(+)tau(-) decays. Upper limits at the 95% C.L on the rate of standard model Higgs boson production are derived in the mass range 100 <= M-H <= 200 GeV. The expected and observed limits are a factor of 6.3 and 8.4 above the predicted standard model cross section at M-H = 125 GeV. We also interpret the data in a fermiophobic Higgs boson model.
|
|
| 23. |
- Abazov, V. M., et al.
(author)
-
Search for the Higgs boson in lepton, tau, and jets final states
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052005-
-
Journal article (peer-reviewed)abstract
- We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9:7 fb(-1) of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H -> tau tau decays or H -> WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0, respectively.
|
|
| 24. |
- Abazov, V. M., et al.
(author)
-
Search for the rare decay B-s(0) -> mu(+) mu(-)
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:7, s. 072006-
-
Journal article (peer-reviewed)abstract
- We perform a search for the rare decay B-s(0) -> mu(+) mu(-) using data collected by the D0 experiment at the Fermilab Tevatron Collider. This result is based on the full D0 Run II data set corresponding to 10.4 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV. We use a multivariate analysis to increase the sensitivity of the search. In the absence of an observed number of events above the expected background, we set an upper limit on the decay branching fraction of B(B-s(0) -> mu(+) mu(-)) < 15 x 10(-9) (12 x 10(-9)) at the 95% (90%) C.L.
|
|
| 25. |
- Abazov, V. M., et al.
(author)
-
Search for the standard model Higgs boson in lv plus jets final states in 9.7 fb(-1) of p(p)over-bar collisions with the D0 detector
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052008-
-
Journal article (peer-reviewed)abstract
- We present, in detail, a search for the standard model Higgs boson, H, in final states with a charged lepton (electron or muon), missing energy, and two or more jets in data corresponding to 9.7 fb(-1) of integrated luminosity collected at a center-of-mass energy of root s = 1.96 TeV with the D0 detector at the Fermilab Tevatron p (p) over bar Collider. The search uses b-jet identification to categorize events for improved signal versus background separation and is sensitive to associated production of the H with a W boson, WH -> lvb(b)over bar>; gluon fusion with the Higgs decaying to W-boson pairs, H -> WW -> lvjj; and associated production with a vector boson where the Higgs decays to W-boson pairs, VH -> VWW -> lvjjjj production (where V = W or Z). We observe good agreement between data and expected background. We test our method by measuring WZ and ZZ production with Z -> b(b)over bar> and find production rates consistent with the standard model prediction. For a Higgs boson mass of 125 GeV, we set a 95% C. L. upper limit on the production of a standard model Higgs boson of 5.8 sigma(SM) SM, where sigma(SM) is the standard model Higgs boson production cross section, while the expected limit is 4.7 X sigma(SM). We also interpret the data considering models with fourth generation fermions, or a fermiophobic Higgs boson.
|
|
| 26. |
- Abazov, V. M., et al.
(author)
-
Search for ZH -> l(+)l(-)b(b)over-bar production in 9.7 fb(-1) of p(p)over-bar collisions with the D0 detector
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052010-
-
Journal article (peer-reviewed)abstract
- We present a search for the standard model Higgs boson produced in association with a Z boson in 9.7 fb(-1) of p (p) over bar collisions collected with the D0 detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. Selected events contain one reconstructed Z -> e(+)e(-) or Z -> mu(+)mu(-) candidate and at least two jets, including at least one jet likely to contain a b quark. To validate the search procedure, we also measure the cross section for ZZ production and find that it is consistent with the standard model expectation. We set upper limits at the 95% C.L. on the product of the ZH production cross section and branching ratio B(H -> b (b) over bar) for Higgs boson masses 90 <= M-H <= 150 GeV. The observed (expected) limit for M-H = 125 GeV is a factor of 7.1 (5.1) larger than the standard model prediction.
|
|
| 27. |
- Abazov, V. M., et al.
(author)
-
Studies of W boson plus jets production in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:9, s. 092001-
-
Journal article (peer-reviewed)abstract
- We present a comprehensive analysis of inclusive W(-> ev) + n-jet (n >= 1, 2, 3, 4) production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Tevatron collider using a 3.7 fb(-1) data set collected by the D0 detector. Differential cross sections are presented as a function of the jet rapidities (y), lepton transverse momentum (P-T) and pseudorapidity (eta), the scalar sum of the transverse energies of the W boson and all jets (H-T), leading dijet P-T and invariant mass, dijet rapidity separations for a variety of jet pairings for P-T-ordered and angular-ordered jets, dijet opening angle, dijet azimuthal angular separations for P-T-ordered and angular-ordered jets, and W boson transverse momentum. The mean number of jets in an event containing a W boson is measured as a function of H-T, and as a function of the rapidity separations between the two highest-P-T jets and between the most widely separated jets in rapidity. Finally, the probability for third-jet emission in events containing a W boson and at least two jets is studied by measuring the fraction of events in the inclusive W + 2-jet sample that contain a third jet over a P-T threshold. The analysis employs a regularized singular value decomposition technique to accurately correct for detector effects and for the presence of backgrounds. The corrected data are compared to particle level next-to-leading-order perturbative QCD predictions, predictions from all-order resummation approaches, and a variety of leading-order and matrix element plus parton shower event generators. Regions of the phase space where there is agreement or disagreement with the data are discussed for the different models tested.
|
|
| 28. |
- Gorbatov, Oleg I., et al.
(author)
-
Role of magnetism in Cu precipitation in alpha-Fe
- 2013
-
In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 88:17, s. 174113-
-
Journal article (peer-reviewed)abstract
- The temperature-dependent solubility of Cu in alpha-Fe and initial stages of Cu precipitation are investigated in first-principles calculations and statistical thermodynamic and kinetic modeling based on ab initio effective interactions. We demonstrate that the weakening of the phase separation tendency with increasing temperature, especially close to the magnetic phase transition, is related to the strong dependence of the "chemical" interactions on the global magnetic state. At the same time, our calculations demonstrate that the vibrational contribution obtained in the quasiharmonic approximation is relatively small for temperatures near the Curie point. The results of Monte Carlo simulations of Cu solubility and clustering are in good agreement with experimental data.
|
|
