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A Study of Factorization and a Measurement of CP Violation
No full textWe report on a study of the decay {bar B}{sup 0} {yields} D*{sup +} {omega}{pi}{sup -} with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232 million B{sup 0}{bar B}{sup 0} decays collected between 1999 and 2004, we measure the branching fraction {Beta}({bar B}{sup 0} {yields} D*{sup +} {omega}{pi}{sup -}) = (2.88 {+-} 0.21(stat.) {+-} 0.31(syst.)) x 10{sup -3}. We study the invariant mass spectrum of the {omega}{pi}{sup -} system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in {tau}{sup -} {yields} {omega}{pi}{sup -} {nu}{sub {tau}}. We also measure the polarization of the D*{sup +} as a function of the {omega}{pi}{sup -} mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*{sup +} to be {Lambda}{sub L}/{Lambda} = 0.654 {+-} 0.042(stat.) {+-} 0.016(syst.). This is in agreement with the expectations from heavy-quark effective theory and factorization assuming that the decay proceeds as {bar B}{sup 0} {yields} D*{sup +} {rho}(1450){sup -}, {rho}(1450){sup -} {yields} {omega}{pi}{sup -}. Furthermore, we present the results on the time-dependent CP asymmetry in neutral B meson decays to the CP eigenstate J/{psi}K{sub L}. The measurements use a data sample of about 88 million {Upsilon}(4S) {yields} B{bar B} decays collected between 1999 and 2002 with the BABAR detector. We study events in which one neutral B meson is fully reconstructed in the J/{psi}K{sub L} final state and the other B meson is determined to be either a B{sup 0} or a {bar B}{sup 0} from its decay products. The amplitude of the CP asymmetry, which in the Standard Model is proportional to sin 2{beta}, is derived from the decay-time distributions in such events. We measure sin 2{beta} = 0.723 {+-} 0.158(stat.) {+-} 0.086(syst.), which is consistent with Standard Model expectations
Measurement of the ratio B(B+-> Xev)/B(B-0 -> Xev)
No full textWe report measurements of the inclusive electron momentum spectra in decays of charged and neutral B mesons, and of the ratio of semileptonic branching fractions B(B+-> Xe nu) and B(B-0 -> Xe nu). These were performed on a sample of 231x10(6) B (B) over bar events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing a hadronic decay of one B meson and identifying an electron among the decay products of the recoiling (B) over bar meson. We obtain B(B+-> Xe nu)/B(B-0 -> Xe nu)=1.074 +/- 0.041((stat))+/- 0.026((syst))
Measurements of the B -> D-* form factors using the decay (B)over-bar(0)-> D(*+)e(-)(v)over-bar(e)
No full textWe measure the dependence of (B) over bar (0)-> D(*+)e(-)(B) over bar (e) on the decay angles and momentum transfer. The data sample consists of similar to 86x10(6) B (B) over bar -pairs accumulated on the Upsilon(4S) resonance by the BABAR detector at the asymmetric e(+)e(-) collider PEP-II. We specify the three form factors by two ratios R-1 and R-2, and by a single parameter rho(2) characterizing the polynomial representing h(A1), the function which describes the momentum-transfer dependence of the form factor A(1). We determine R-1, R-2, and rho(2) using an unbinned maximum likelihood fit to the full decay distribution. The results are R-1=1.396 +/- 0.060 +/- 0.035 +/- 0.027, R-2=0.885 +/- 0.040 +/- 0.022 +/- 0.013, and rho(2)=1.145 +/- 0.059 +/- 0.030 +/- 0.035. The stated uncertainties are the statistical from the data, statistical from the size of the Monte Carlo sample and the systematic uncertainty, respectively. In addition, based on this measurement, we give an updated value for the CKM matrix element vertical bar V-cb vertical bar
A Measurement of the inclusive b ---> s gamma branching ratio
No full textThe flavour changing neutral current decay b -> s gamma has been detected in hadronic Z decays collected by ALEPH at LEP. The signal is isolated in lifetime-tagged b-bbar events by the presence of a hard photon associated with a system of high momentum and high rapidity hadrons. The background processes are normalised from the data themselves. The inclusive branching ratio is measured to be 3.11 +- 0.80_stat +- 0.72_syst DistList PSforwarding done files helpND.html images insert_new.sh insert_new.sh~ log modify modifying pending running waiting 10**-4, consistent with the Standa rd Model expectation via penguin processes
Measurement of WZ and ZZ production in pp collisions at √s = 8 TeV in final states with b-tagged jets
No full textOpen Access This article is distributed under the terms of the Creative
Commons Attribution License which permits any use, distribution, and
reproduction in any medium, provided the original author(s) and the
source are credited.
Funded by SCOAP3 / License Version CC BY 4.0.Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at s √ =8 TeV in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either W→eν , μν or Z→e + e − , μ + μ − , or νν ¯ ). The results are based on data corresponding to an integrated luminosity of 18.9 fb −1 collected with the CMS detector at the Large Hadron Collider. The measured cross sections, σ(pp→WZ)=30.7±9.3(stat.)±7.1(syst.)±4.1(th.)±1.0(lum.)pb and σ(pp→ZZ)=6.5±1.7(stat.)±1.0(syst.)±0.9(th.)±0.2(lum.)pb , are consistent with next-to-leading order quantum chromodynamics calculationsBMWF and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil);
MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CS (Croatia); RPF (Cyprus); MoER, SF0690030s09 and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF(Germany);GSRT(Greece);OTKAand NIH(Hungary);DAEand DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Republic of Korea); LAS (Lithuania);MOE and UM(Malaysia); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland);
NSC (Taipei); ThEPCenter, IPST, STAR and NSTDA(Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA)
Search for decays of B-0 -> e(+)e(-), B-0 -> mu(+)mu(-), B-0 -> e(+/-)mu(-/+)
No full textWe present a search for the decays B-0 -> e(+)e(-), B-0 ->mu(+)mu(-), and B-0 -> e(+/-)mu(-/+) in data collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC B Factory. Using a data set of 111 fb(-1), we find no evidence for a signal in any of the three channels investigated and set the following branching fraction upper limits at the 90% confidence level: B(B-0 -> e(+)e(-))mu(+)mu(-)) e(+/-)mu(-/+))< 18x10(-8)
Observation of B**0 ---> omega K0, B+ ---> eta pi+, and B+ ---> eta K+ and study of related decays
No full textWe present measurements of branching fractions and charge asymmetries for seven B-meson decays with an eta, eta('), or omega meson in the final state. The data sample corresponds to 89x10(6) B (B) over bar pairs produced from e(+)e(-) annihilation at the Y(4S) resonance. We measure the following branching fractions in units of 10(-6): B(B+-->etapi(+))=5.3+/-1.0+/-0.3, B(B+-->etaK(+))=3.4+/-0.8+/-0.2, B(B-0-->etaK(0))=2.9+/-1.0+/-0.2 (eta(')pi(+))=2.7+/-1.2+/-0.3 (omegapi(+))=5.5+/-0.9+/-0.5, B(B+-->omegaK(+))=4.8+/-0.8+/-0.4, and B(B-0-->omegaK(0))=5.9(-1.3)(+1.6)+/-0.5. The charge asymmetries are A(ch)(B+-->etapi(+))=-0.44+/-0.18+/-0.01, A(ch)(B+-->etaK(+))=-0.52+/-0.24+/-0.01, A(ch)(B+-->omegapi(+))=0.03+/-0.16+/-0.01, and A(ch)(B+-->omegaK(+))=-0.09+/-0.17+/-0.01
Search for B+→τ+ν
No full textWe present a search for the decay B+->tau(+)nu using 383x10(6)B (B) over bar pairs collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed semileptonic B decay (B--> D(0)l - (v) over bar lX) is selected, and in the recoil a search for B+-> tau(+)nu is performed. The tau is identified in the following channels: tau(+)-> e(+)nu(v) over bar, tau(+)->mu(+)nu(v) over bar, tau(+)->pi(+)(v) over bar, and tau(+)->pi(+)pi(0)(v) over bar. We measure a branching fraction of B(B+->tau(+)nu)=(0.9 +/- 0.6(stat.)+/- 0.1(syst.))x10(-4). In the absence of a significant signal, we calculate an upper limit at the 90% confidence level of B(B+->tau(+)nu)< 1.7x10(-4). We calculate the product of the B meson decay constant f(B) and vertical bar V-ub vertical bar to be f(B)center dot vertical bar V-ub vertical bar=(7.2(-2.8)(+2.0)(stat.)+/- 0.2(syst.))x10(-4) GeV
Search for the decay B-0 -> p(p)over-bar
No full textWe present the result of a search for the charmless two-body baryonic decay
B
0
→
p
̄
p
in a sample of 88 million
Υ
(
4
S
)
→
B
̄
B
decays collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. We use Cherenkov radiation to identify protons cleanly, and determine the signal yield with a maximum-likelihood fit technique using kinematic and topological information. We find no evidence for a signal and place a 90% confidence-level upper limit of
B
(
B
0
→
p
̄
p
)
<
2.7
×
10
−
7
Measurement of B decays to ϕKγ
No full textWe search for the decays B-->phi K-gamma and (B) over bar (0)->phi(K) over bar (0)gamma in a data sample of 228x10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance with the BABAR detector. We measure the branching fraction B(B-->phi K-gamma)=(3.5 +/- 0.6 +/- 0.4)x10(-6) and set an upper limit B((B) over bar (0)->phi($) over bar (0)gamma)phi K-gamma, A(CP)=(-26 +/- 14 +/- 5)%. The uncertainties are statistical and systematic, respectively
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