4,637 research outputs found
Charmless three-body decays of b-hadrons
A review of recent results from LHCb and the B-factories on the charmless
decays of b-hadrons into three-body final states is presented.Comment: 14 pages, 13 figures. Presentation at the DPF 2013 Meeting of the
American Physical Society Division of Particles and Fields, Santa Cruz,
California, August 13-17, 201
Observation of the rare decay B+ -> K+Ļ0Ļ0 and measurement of the quasi-two-body contributions B+ -> K*(892)+Ļ0, B+ -> f0(980)K+, and B+ -> Ļc0K+
We report an analysis of charmless hadronic decays of charged B mesons to the final state K(+) pi(0)pi(0), using a data sample of (470.9 +/- 2.8) x 10(6) B (B) over bar events collected with the BABAR detector at the Y(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be B(B(+) -> K(+) pi(0)pi(0)) = (16.2 +/- 1.2 +/- 1.5) x 10(-6) and A(CP)(B(+) -> K(+) pi(0)pi(0)) = -0.06 +/- 0.06 +/- 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B(+) -> K*(892)(+) pi(0), B(+) -> f(0)(980)K(+), and B(+) -> chi(c0)K(+) quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B(+) -> K(+) pi(0)pi(0) and B(+) -> K(+)(892)(+) pi(0) channels
First observation of Bs0 ā D*s2+XĪ¼-Ī½ decays
Using data collected with the LHCb detector in protonāproton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays B0sāD+sXĪ¼āĪ½ and B0sāD0K+XĪ¼āĪ½ are detected. Two structures are observed in the D0K+ mass spectrum at masses consistent with the known Ds1(2536)+ and Dās22573)+ mesons. The measured branching fractions relative to the total B0s semileptonic rate are B(B0sāDā+s2XĪ¼āĪ½)/B(B0sāXĪ¼āĪ½) = (3.3Ā±1.0Ā±0.4)%, and B(B0sāD+s1XĪ¼āĪ½)/B(B0sāXĪ¼āĪ½) = (5.4Ā±1.2Ā±0.5)%, where the ļ¬rst uncertainty is statistical and the second is systematic. This is the ļ¬rst observation of the Dā+s2 state in B0s decays; we also measure its mass and width
Spin orbit alignment for KELT-7b and HAT-P-56b via Doppler tomography with TRES
We present Doppler tomographic analyses for the spectroscopic transits of
KELT-7b and HAT-P-56b, two hot-Jupiters orbiting rapidly rotating F-dwarf host
stars. These include analyses of archival TRES observations for KELT-7b, and a
new TRES transit observation of HAT-P-56b. We report spin-orbit aligned
geometries for KELT-7b (2.7 +/- 0.6 deg) and HAT-P-56b (8 +/- 2 deg). The host
stars KELT-7 and HAT-P-56 are among some of the most rapidly rotating
planet-hosting stars known. We examine the tidal re-alignment model for the
evolution of the spin-orbit angle in the context of the spin rates of these
stars. We find no evidence that the rotation rates of KELT-7 and HAT-P-56 have
been modified by star-planet tidal interactions, suggesting that the spin-orbit
angle of systems around these hot stars may represent their primordial
configuration. In fact, KELT-7 and HAT-P-56 are two of three systems in
super-synchronous, spin-orbit aligned states, where the rotation periods of the
host stars are faster than the orbital periods of the planets.Comment: 9 pages, accepted for publication in MNRA
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Study of Multi-body Charmless B Decays with the BaBar Experiment
The authors report recent measurements of charmless B decays to the final states K{sup +}K{sup +}K{sup -}, {phi}{phi}K, {eta}'{eta}'K, M{sub S}{sup 0}K{sub S}{sup 0}K{sub L}{sup 0}, {bar {Lambda}}p{pi}{sup +}, K*{sup +}h{sup +}h{sup -} and KX(inclusive). The results were obtained using a data sample of up to 288.5 fb{sup -1} recorded by the BABAR detector at the PEP-II asymmetric B factory at SLAC
Measurement of the resonant and CP components in BĀÆ 0 ā J=ĻĻĆ¾Ļā decays
The resonant structure of the reaction BĀÆ0āJ/ĻĻ+Ļā is studied using data from 3āāfbā1 of integrated luminosity collected by the LHCb experiment, one third at 7 TeV center-of-mass energy and the remainder at 8 TeV. The invariant mass of the Ļ+Ļā pair and three decay angular distributions are used to determine the fractions of the resonant and nonresonant components. Six interfering Ļ+Ļā states, Ļ(770), f0(500), f2(1270), Ļ(1450), Ļ(782) and Ļ(1700), are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative charge parity fractions of each of the resonant final states are determined. The f0(980) meson is not seen and the upper limit on its presence, compared with the observed f0(500) rate, is inconsistent with a model where these scalar mesons are formed from two quarks and two antiquarks (tetraquarks) at the eight standard deviation level. In the qqĀÆ model, the absolute value of the mixing angle between the f0(980) and the f0(500) scalar mesons is limited to be less than 17Ā° at 90% confidence level
Study of beauty hadron decays into pairs of charm hadrons
First observations of the decays Īb 0 ā Īc +D(s) - are reported using data corresponding to an integrated luminosity of 3fb-1 collected at 7 and 8 TeV center-of-mass energies in proton-proton collisions with the LHCb detector. In addition, the most precise measurement of the branching fraction B(Bs 0āD+Ds -) is made and a search is performed for the decays B(s) 0āĪc +Īc -. The results obtained are B(Īb 0āĪc +D-)/ B(Īb 0āĪc +D s -)=0.042Ā±0.003(stat)Ā±0.003(syst), [B(Īb 0āĪc +D s -)/B(BĢ0āD+D s -)]/[B(Īb 0āĪ c +Ļ-)/B(BĢ0āD +Ļ-)]=0.96Ā±0.02(stat)Ā±0.06(syst),B(B s 0āD+Ds -)/ B(BĢ0āD+Ds -)=0. 038Ā±0.004(stat)Ā±0.003(syst),B(BĢ0āĪ c +Īc -)/B(BĢ 0āD+Ds -)<0.0022[95%C.L.], B(Bs 0āĪc +Ī c -)/B(Bs 0āD+D s -)<0.30[95%C.L.]. Measurement of the mass of the Īb 0 baryon relative to the BĢ0 meson gives M(Īb 0)-M(BĢ0)=339. 72Ā±0.24(stat)Ā±0.18(syst)MeV/c2. This result provides the most precise measurement of the mass of the Īb 0 baryon to date
Measurement of CP asymmetry in D 0 ā K - K + and D 0 ā Ļ - Ļ decays
Time-integrated CP asymmetries in D 0 decays to the final states K - K + and Ļ - Ļ + are measured using proton-proton collisions corresponding to 3fb-1 of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D 0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be Ī ACP = ACP (K- K +) ACP (Ļ- Ļ+) = (+ 0.14 Ā± 0.16 (stat) Ā± 0.08 (syst)) %. A measurement of A CP (K - K +) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be ACP (K- K+) = (- 0.06 Ā± 0.15 (stat) Ā± 0.10 (syst)) %, where the correlation coefficient between ĪA CP and A CP (K - K +) is Ļ = 0.28. By combining these results, the CP asymmetry in the D 0 ā Ļ - Ļ + channel is A CP (Ļ - Ļ +) = (-0.20 Ā± 0.19 (stat) Ā± 0.10 (syst))%
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