A Swarm of Bs

New physics signals containing five or more b-tagged jets, but without MET or leptons, could realistically be sitting within the current 8 TeV LHC data set without receiving meaningful constraints from any of the existing LHC searches at either ATLAS or CMS. This work provides several examples of simple, motivated models that yield final states containing many b-jets. To study the potential for uncovering new physics in these high b-jet multiplicity channels, this paper focuses on a natural supersymmetry scenario where each of the pair-produced stops decays to an on-shell chargino, which subsequently decays via an MFV-motivated, R-parity violating coupling. This gives rise to an eight-jet final state containing six b-quarks. Although no public measurements exist, estimates indicate that the standard model backgrounds in high b-jet multiplicity channels should be very small. To circumvent the background uncertainty, an asymmetric method is presented that utilizes two different techniques to conservatively exclude or to discover new physics in high b-jet multiplicity final states.Comment: 14 pages, 4 figures, 2 tables, journal versio

Measurement of B[Y(5S)->Bs(*) anti-Bs(*)] Using phi Mesons

Knowledge of the Bs decay fraction of the Y(5S) resonance, fs, is important for Bs meson studies at the Y(5S) energy. Using a data sample collected by the CLEO III detector at CESR consisting of 0.423/fb on the Y(5S) resonance, 6.34/fb on the Y(4S) and 2.32/fb in the continuum below the Y(4S), we measure B(Y(5S) -> phi X)=(13.8 +/- 0.7 {+2.3}{-1.5})% and B(Y(4S) -> phi X) = (7.1 +/- 0.1 +/-0.6)%; the ratio of the two rates is (1.9 +/- 0.1 {+0.3}{-0.2}). This is the first measurement of the phi meson yield from the Y(5S). Using these rates, and a model dependent estimate of B(Bs -> phi X), we determine fs = (24.6 +/- 2.9 {+11.0}{-5.3})%. We also update our previous independent measurement of fs made using the inclusive Ds yields to now be (16.8 +/- 2.6 {+6.7}{-3.4)%, due to a better estimate of the number of hadronic events. We also report the total Y(5S) hadronic cross section above continuum to be sigma(e^+e^- -> Y(5S))=(0.301 +/- 0.002 +/- 0.039) nb. This allows us to extract the fraction of B mesons as (58.9+/-10.0+/-9.2)%, equal to 1-fs. averaging the three methods gives a model dependent result of fs=(21 {+6}{-3})%.Comment: 23 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2006/, Submitted to PR

Semileptonic BsB_s decay measurements at LHCb

I discuss the first semileptonic $B_s$ decay measurements performed at LHCb, and the prospects for precise studies of $B_s$ semileptonic decay properties. The analyses covered here are based on data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV. In particular the semileptonic decays \Bs\to D_s^+ X \munu and \Bs\to D^0K^+ X \munu are studied. Two structures are observed in the $D^0K^+$ mass spectrum at masses consistent with the known $D_{s1}(2536)^+$ and $D^*_{s2}(2573)^{+}$ mesons. The measured branching fractions relative to the total \Bs semileptonic rate are {{\cal{B}}(\Bs\to D_{s2}^{*+} X \munu)}/{{\cal{B}}(\Bs\to X \munu)}= (3.3\pm 1.0\pm 0.4)%, and {{\cal{B}}(\Bs\to D_{s1}^+ X \munu)}/{{\cal{B}}(\Bs\to X \munu)}= (5.4\pm 1.2({\rm stat})\pm 0.5({\rm sys}))%. This is the first observation of the $D_{s2}^{*+}$ state in \Bs decays.Comment: Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 201

CP violation with Bs

The observation of CP violation effects is becoming more and more significant in a variety of channels, due to the impressive experimental effort of the last years. We review recent progress in Bs semileptonic decays and in Bs decays into CP eigenstates.Comment: 4 pages. To appear in Proceedings of Rencontres de Moriond, QCD and High Energy Interactions, La Thuile, March 10-17, 201