scholarly journals Constraints on the CKM angle α in the B → ρρ decays

2005 ◽  
Vol 20 (15) ◽  
pp. 3578-3580
Author(s):  
Haibo Li
Keyword(s):  
Decay Mode ◽  
Branching Fraction ◽  
Time Dependent ◽  
Penguin Contribution ◽  
Upper Limit ◽  
B Factory ◽  
Babar Detector ◽  
Asymmetry Parameters ◽  
Ckm Angle

Using a data sample of 122 million [Formula: see text] decays collected with BABAR detector at the PEP-II asymmetric B factory at SLAC, we measure the time-dependent-asymmetry parameters of the longitudinally polarized component in the B0 → ρ+ρ- decay as CL = -0.23 ± 0.24 ( stat ) ± 0.14 ( syst ) and SL = -0.19 ± 0.33 ( stat ) ± 0.11 ( syst ). The B0 → ρ0ρ0 decay mode is also searched for in a data sample of about 227 million [Formula: see text] pairs. No significant signal is observed, and an upper limit of 1.1 × 10-6 (90% C.L.) on the branching fraction is set. The penguin contribution to the CKM angle α uncertainty is measured to be 11°. All results are preliminary.

A SEARCH FOR THE DECAY B+ → τ+ντ AT BABAR

2005 ◽  
Vol 20 (16) ◽  
pp. 3695-3697
Author(s):  
◽  
MOUSUMI DATTA
Keyword(s):  
Confidence Level ◽  
Branching Fraction ◽  
Upper Limit ◽  
B Factory ◽  
Babar Detector

We present a search for the decay B+ → τ+ντ in [Formula: see text] decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay [Formula: see text] is selected, and in the recoil a search for B+ → τ+ ντ signal is performed. The τ is identified in the following channels: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. We find no evidence of signal, and we set a preliminary upper limit on the branching fraction of [Formula: see text] at the 90% confidence level (CL). This result is then combined with a statistically independent BABAR search for B+ → τ+ντ to give a combined preliminary limit of [Formula: see text] at 90% CL.

Partial Reconstruction of $B^0 \to D_s^{*+}D^{*-}$ Decays and Measurement of the $D_s^+ \to \phi\pi^+$ Branching Fraction

2005 ◽  
Vol 20 (16) ◽  
pp. 3712-3715
Author(s):  
Silvia Pennazzi
Keyword(s):  
Branching Fraction ◽  
Branching Fractions ◽  
Reconstruction Technique ◽  
Preliminary Results ◽  
Partial Reconstruction ◽  
Full Reconstruction ◽  
B Factory ◽  
Babar Detector

We present preliminary results on the branching fractions [Formula: see text] and [Formula: see text], based on a data sample of approximately [Formula: see text] events collected by the BABAR detector at the PEP-II e+e-B–factory. We reconstruct B0 mesons using both a partial and a full reconstruction technique. We obtain the following preliminary results: [Formula: see text] where the first error in each measurement is statistical, the second systematic.

REDUCING THE EXPERIMENTAL UNCERTAINTY ON THE CKM ANGLE α

1999 ◽  
Vol 14 (22) ◽  
pp. 1461-1477
Author(s):  
P. COLANGELO ◽  
L. IORIO ◽  
G. NARDULLI
Keyword(s):  
Error Analysis ◽  
Working Conditions ◽  
Time Dependent ◽  
Experimental Uncertainty ◽  
B Decays ◽  
B Factory ◽  
Neutral B Decays ◽  
Ckm Angle

We investigate possible strategies to reduce the experimental uncertainty on the CKM angle α, in the working conditions of an asymmetric e+ e-B-factory. We propose to use information from the time-dependent asymmetry of neutral B-decays to π+ π-, together with the ratio [Formula: see text]. We also consider the possibility of using information on the ratio [Formula: see text]. An error analysis on α depending on the expected experimental uncertainties on the input quantities is carried out.

Measurement of CP-Violating Asymmetries in B0 → (ρπ)0 Using a Time-Dependent Dalitz Plot Analysis

2005 ◽  
Vol 20 (15) ◽  
pp. 3551-3553
Author(s):  
◽  
ATTILA MIHALYI
Keyword(s):  
Form Factor ◽  
Maximum Likelihood ◽  
Decay Rate ◽  
Bilinear Form ◽  
Dalitz Plot ◽  
Time Dependent ◽  
Preliminary Measurement ◽  
Plot Analysis ◽  
B Factory ◽  
Babar Detector

We present the preliminary measurement of CP-violating asymmetries in B0 → (ρπ)0 → π+π-π0 decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 213 million [Formula: see text] decays, collected by the BaBar detector at the PEPII asymmetric-energy B -Factory at SLAC. We measure 16 coefficients of the bilinear form factor terms occurring in the time-dependent decay rate of the B0 meson with the use of a maximum-likelihood fit. The physically relevant CP parameters are derived from these coefficients.

scholarly journals A Study of $B^+ \to p{\bar p}K^+$ and a Search for a Θ*++ Pentaquark Candidate in B Decay

2005 ◽  
Vol 20 (16) ◽  
pp. 3749-3752 ◽  
Author(s):  
◽  
Tetiana Berger-Hryn'ova
Keyword(s):  
Confidence Level ◽  
Branching Fraction ◽  
Upper Limit ◽  
Narrow State ◽  
Babar Detector

A study of the decay [Formula: see text] is performed using 81 fb-1 of data collected at the ϒ(4 S ) with the BABAR detector at PEP-II. The branching fraction of [Formula: see text] is measured to be (6.7 ± 0.9 ± 0.6) × 106. An upper limit on the branching fraction of [Formula: see text], where Θ*++ is a narrow state decaying to pK+, is set to be 1.5 × 10-7 for 1.43 < m(Θ*++) < 1.85 GeV/c 2 at 90% confidence level. All results are preliminary.

scholarly journals Search for the rare semi-leptonic decay J/ψ → D−e+νe + c.c.

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
◽  
M. Ablikim ◽  
M. N. Achasov ◽  
P. Adlarson ◽  
S. Ahmed ◽  
...  
Keyword(s):  
Confidence Level ◽  
Branching Fraction ◽  
Center Of Mass ◽  
Leptonic Decay ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Upper Limit ◽  
Electron Positron

Abstract Using 10.1 × 109J/ψ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy $$ \sqrt{s} $$ s = 3.097 GeV and collected with the BESIII detector, we present a search for the rare semi-leptonic decay J/ψ → D−e+νe + c.c. No excess of signal above background is observed, and an upper limit on the branching fraction ℬ(J/ψ → D−e+νe + c. c.) < 7.1 × 10−8 is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.

scholarly journals Search for dark photons in Higgs boson production via vector boson fusion in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Branching Fraction ◽  
Vector Boson ◽  
Boson Mass ◽  
Higgs Boson Mass ◽  
Vector Boson Fusion ◽  
Upper Limit ◽  
The Standard Model

Abstract A search is presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle and an isolated photon. The search is performed by the CMS collaboration at the LHC, using a data set corresponding to an integrated luminosity of 130 fb−1, recorded at a center-of-mass energy of 13 TeV in 2016–2018. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for production via vector boson fusion and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a Higgs boson mass of 125 GeV, assuming the standard model production rates, the observed (expected) 95% confidence level upper limit on the branching fraction is 3.5 (2.8)%. This is the first search for such decays in the vector boson fusion channel. Combination with a previous search for Higgs bosons produced in association with a Z boson results in an observed (expected) upper limit on the branching fraction of 2.9 (2.1)% at 95% confidence level.

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