arXiv subjects

V. Abazov et al

Publications and source records attributed to V. Abazov et al.

5 recordsLinked to original sources

arXiv2010

Search for the rare decay B_s^0->mu^+mu^-

We present the results of a search for the flavor changing neutral current decay B_s^0->mu^+mu^- using 6.1 fb^-1 of ppbar collisions at sqrt(s) = 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron Collider. The observed number of B_s^0 candidates is consistent with background expectations. The resulting upper limit on the branching fraction is BR(B_s^0->mu^+mu^-) < 5.1 x 10^-8 at the 95% C.L. This limit is a factor of 2.4 better than that of the previous D0 analysis and the best limit to date.

hep-ex↗

arXiv2010

Evidence for an anomalous like-sign dimuon charge asymmetry

We measure the charge asymmetry $A\equiv(N^{++} - N^{--})/(N^{++} + N^{--})$ of like-sign dimuon events in 6.1~fb$^{-1}$ of $p\bar{p}$ collisions recorded with the D0 detector at a center-of-mass energy $\sqrt{s}=1.96$~TeV at the Fermilab Tevatron collider. From $A$ we extract the like-sign dimuon charge asymmetry in semileptonic $b$-hadron decays: $\aslb=-0.00957\pm0.00251\thinspace({\rm stat})\pm0.00146\thinspace({\rm sys})$. It differs by 3.2~standard deviations from the standard model prediction $\aslb({\rm SM})=(-2.3^{+0.5}_{-0.6})\times10^{-4}$, and provides first evidence of anomalous $CP$ violation in the mixing of neutral $B$ mesons.

hep-ex↗

arXiv2010

Measurement of the $WZ\rightarrow \ellν\ell\ell$ cross section and limits on anomalous triple gauge couplings in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV

We present a new measurement of the $WZ\rightarrow \ellν\ell\ell$ ($\ell = e,μ$) cross section and limits on anomalous triple gauge couplings. Using 4.1 fb$^{-1}$ of integrated luminosity of $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV, we observe 34 $WZ$ candidate events with an estimated background of $6.0 \pm 0.4$ events. We measure the $WZ$ production cross section to be $3.90^{+1.06}_{-0.90}$ pb, in good agreement with the standard model prediction. We find no evidence for anomalous $WWZ$ couplings and set 95% C.L. limits on the coupling parameters, $-0.075 < λ_{Z} < 0.093$ and $-0.027 < Δκ_{Z} < 0.080$, in the HISZ parameterization for a $Λ= 2$ TeV form factor scale. These are the best limits to date obtained from the direct measurement of the $WWZ$ vertex.

hep-ex↗

arXiv2007

Observation and properties of the orbitally excited B_{s2}* Meson

We report the direct observation of the excited L=1 state B_{s2}* in fully reconstructed decays to B+K-. The mass of the B_{s2}* meson is measured to be {5839.6 +- 1.1 (stat.) +- 0.7 (syst.) MeV/c^2, and its production rate relative to the B+ meson is measured to be [1.15 +- 0.23 (stat.) +- 0.13 (syst.)] %.

hep-ex↗

arXiv2007

Measurement of the top quark mass in the dilepton channel

We present a measurement of the top quark mass in the dilepton channel based on approximately 370/pb of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m_t = 178.1 +/- 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.

hep-ex↗