Author: Ahmed AliPublisher:
ISBN:
Category :
Languages : de
Pages :
Book Description
Rare radiative B-decays in the standard model
Author: Ahmed AliA Search for the Rare Decay [B Meson to Two Photons]
![A Search for the Rare Decay [B Meson to Two Photons] PDF](https://books.google.com/books/content/images/frontcover/Wz2qAQAACAAJ?fife=w80-h100)
Author: Andrew Michael RulandPublisher:
ISBN:
Category :
Languages : en
Pages : 362
Book Description
This thesis describes a search for the rare radiative decay of a B meson to two photons. where the charged congugate mode is implied throughout. These decays are highly suppressed in the Standard Model where the branching fraction is expected to be of order 10^-8. In some new physics scenarios this could be enhanced by up to an order of magnitude to 10^-7. Therefore an observation of a significant signal above the Standard Model prediction could be a sign of new physics. The search for this rare decay was performed using the data collected with the BaBar detector at the SLAC National Accelerator Laboratory PEP-II storage ring operating at the Upsilon(4S) resonance. The analysis uses a dataset with an integrated luminosity of 425.7 fb-1 corresponding to 467 million BB pairs. A signal yield of 21.3 +12.8 -11.8 events with a significance of 1.88 sigma was measured using an unbinned extended maximum likelihood fit. An upper limit on the branching fraction is set at the 90% confidence level of less than 3.2 times 10^-7. This is about two times more stringent than the best upper limit of less than 6.2 times 10^-7 published by the Belle collaboration.
Inclusive Rare B Decays Using Effective Field Theories
Author: Christian BauerPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
In this thesis we will discuss several properties of rare decays of ' B' mesons. First we discuss properties of the inclusive radiative decay 'B¢' [right arrow] 'Xs'ã, where 'Xs' stands for any hadronic state containing an 's' quark. We extend previous studies of this decay, which included perturbative corrections to order Ã's' and nonperturbative contributions up to order ([Lambda]QCD/' mb')2 and calculate the O ([Lambda]QCD/'mb')3 contributions to this decay. The values of the nonperturbative parameters entering at this order are unknown, leading to uncertainties in the standard model prediction of this decay. We estimate the size of these nonperturbative uncertainties by varying these parameters in the range suggested by dimensional analysis. We also estimate uncertainties arising from a cut on the photon energy which is required experimentally. Another decay mode investigated is 'B¢' [right arrow] ' Xs'3⁄4+3⁄4-. We study the O ([Lambda]QCD/'mb')3 contributions to the leptonic invariant mass spectrum, the forward-backward asymmetry and hadronic invariant mass moments and estimate the resulting uncertainties. We calculate how the size of these uncertainties depend on the value of an experimental cut that has to be applied to eliminate the large background from other 'B' decays. A model independent way to determinate the CKM matrix element @' Vub'@ from the dilepton invariant mass spectrum of the inclusive decay B[right arrow]Xu3⁄4+ n is presented next. We show that cuts required to eliminate the charm background still allow for a theoretically clean way to determine the CKM matrix element @'Vub'@. We also discuss the utility of the 'B¢' [right arrow] 'Xs'3⁄4 +3⁄4- decay rate above the y (2'S') resonance to reduce the resulting uncertainties. Finally, we introduce a novel effective theory valid for highly energetic particles. In decays where the phase space is sufficiently restricted such that final state particles have very high energies compared to their mass, the perturbative as well as nonperturbative series diverge. The effective theory presented allows to sum perturbative Sudakov logarithms in a framework that also incorporates the nonperturbative physics in such limits of phase space.
Rare Radiative [Beta] Decays in the Standard Model
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Author: B Decays (Revised 2nd Edition)
Author: Sheldon StonePublisher: World Scientific
ISBN: 9814583308
Category : Science
Languages : en
Pages : 673
Book Description
This 2nd edition is an extensive update of 'B Decays”. The revisions are necessary because of the extensive amount of new data and new theoretical ideas. This book reviews what is known about b-quark decays and also looks at what can be learned in the future.The importance of this research area is increasing, as evidenced by the approval of the luminosity upgrade for CESR and the asymmetric B factories at SLAC and KEK, and the possibility of experiments at hadron colliders.The key experimental observations made thus far, measurement of the lifetimes of the different B species, B0-B0 mixing, the discovery of “Penguin” mediated decays, and the extraction of the CKM matrix elements Vub and Vcb from semileptonic decays, as well as more mundane results, are described in great detail by the experimentalists who have been closely involved with making the measurements. Theoretical progress in understanding b-quark decays using HQET and lattice gauge techniques are described by theorists who have developed and used these techniques.Synthesizing the experimental and theoretical information, several articles discuss the implications for the “Standard Model” and how further tests can be done using measurements of CP violation in the B system.
Radiative B Decays
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
We summarize the constraints placed on physics beyond the Standard Model from the recent CLEO observations of the exclusive decay B → K*[gamma] and bound on the inclusive model b → s[gamma].
B Decays
Author: Sheldon StonePublisher: World Scientific
ISBN: 9789810218362
Category : Science
Languages : en
Pages : 676
Book Description
This 2nd edition is an extensive update of "B Decays?. The revisions are necessary because of the extensive amount of new data and new theoretical ideas. This book reviews what is known about b-quark decays and also looks at what can be learned in the future.The importance of this research area is increasing, as evidenced by the approval of the luminosity upgrade for CESR and the asymmetric B factories at SLAC and KEK, and the possibility of experiments at hadron colliders.The key experimental observations made thus far, measurement of the lifetimes of the different B species, B0-B0 mixing, the discovery of ?Penguin? mediated decays, and the extraction of the CKM matrix elements Vub and Vcb from semileptonic decays, as well as more mundane results, are described in great detail by the experimentalists who have been closely involved with making the measurements. Theoretical progress in understanding b-quark decays using HQET and lattice gauge techniques are described by theorists who have developed and used these techniques.Synthesizing the experimental and theoretical information, several articles discuss the implications for the ?Standard Model? and how further tests can be done using measurements of CP violation in the B system.
'95 Electroweak Interactions and Unified Theories
Author: J. Thanh Van TranPublisher: Atlantica Séguier Frontières
ISBN: 9782863321850
Category : Electromagnetic interactions
Languages : en
Pages : 574
Book Description
B physics overview
Author: Martin BenekeB Physics: Physics Beyond The Standard Model At The B Factory - Proceedings Of The 1994 International Workshop
Author: S SuzukiPublisher: World Scientific
ISBN: 9814549398
Category :
Languages : en
Pages : 494
Book Description
This volume reviews the recent progress of B physics, and discusses theoretical and experimental aspects of the physics which will be explored at the B factory. CP violation and new physics beyond the Standard Model are the main issues of the discussion.