Search for New Physics Using Radiative B Meson Decays and Lifetime Measurment of the B Meson with the Belle II Experiment
Search for New Physics Using Radiative B Meson Decays and Lifetime Measurment of the B Meson with the Belle II Experiment

Author: Reem Rasheed

Publisher:

Published: 2020

Total Pages: 0

ISBN-13:

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After the Big Bang matter and antimatter were present in equal amounts. Today, however, everything we see, is made almost entirely of matter. A fundamental ingredient to explain this asymmetry between matter and antimatter is the violation of the CP (Charge Parity) symmetry. CP violation has been observed but quantitatively not enough to explain the huge asymmetry. The Belle II experiment in Japan studies the particles produced in electron-positron collisions at the SuperKEKB collider, the highest intensity collider in the World, allowing a high precision measurements of the known sources of CP violation and looking for new ones. In my PhD, I worked on measuring the CP violation in B meson radiative decays (decays with photon in final state) particularly promising thanks to their high sensitivity to possible new processes. Following this analysis, I started a new measurement of the B mesons lifetime where I could verify the robustness of the tools used in the CP violation measurement.

B Decays
B Decays

Author: Sheldon Stone

Publisher: World Scientific

Published: 1994

Total Pages: 676

ISBN-13: 9789810218362

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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.

Inclusive Semileptonic B Decays at BABAR.
Inclusive Semileptonic B Decays at BABAR.

Author:

Publisher:

Published: 2004

Total Pages:

ISBN-13:

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The authors report updates on two analyses of inclusive semileptonic B decays based on a dataset of 89 million B[bar B] events recorded with the BABAR detector at the [Upsilon](4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other [bar B] meson. IN the first analysis, the measurement of the first and second moment of the hadronic mass distribution in Cabibbo-favored [bar B] [yields] X[sub c][ell][bar [nu]] decays allows for the determination of the nonperturbative parameters [bar [Lambda]] and [lambda][sub 1] of Heavy Quark Effective Theory (HQET) and V[sub cb]. In the second analysis, the hadronic mass distribution is used to measure the inclusive charmless semileptonic branching fraction and to determine V[sub ub].

Study of Exclusive Semileptonic B Meson Decays ToTau Leptons
Study of Exclusive Semileptonic B Meson Decays ToTau Leptons

Author:

Publisher:

Published: 2007

Total Pages: 359

ISBN-13:

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We present the results of a search for four exclusive semileptonic decays B → D{sup (*)}[tau]−{bar [nu]}{sub [tau]} in 209 fb−1 of data collected with the BABAR detector, corresponding to 232 million e+e- → [Upsilon](4S) → B{bar B} events. We select events with a D{sup (*)} meson and a light lepton (e or [mu]) recoiling against a fully-reconstructed B meson. We perform a fit to the lepton spectrum and missing mass squared to discriminate signal events from backgrounds, predominantly B → D{sup (*)}{tau}−{bar [nu]}{sub {tau}}. A control sample of identified D**l−{bar {nu}}{sub {ell}} events is included in the fit to estimate the background contribution from these decays. We measure [beta](B → D{sub {tau}{nu}}) = (0.86±0.24±0.11±0.06)% and [beta](B → D*{sub {tau}{nu}}) = (1.62±0.31±0.10±0.05)%, where the errors are statistical, systematic, and normalization-mode related, respectively, and where the results are expressed for the {bar B}° lifetime.

Preliminary Measurement of Time-dependent B[sub D][sup 0]-B[sub D][sup 0] Mixing Using Topology and Charge Selected Semi-leptonic B Decays
Preliminary Measurement of Time-dependent B[sub D][sup 0]-B[sub D][sup 0] Mixing Using Topology and Charge Selected Semi-leptonic B Decays

Author:

Publisher:

Published: 2001

Total Pages:

ISBN-13:

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The time dependence of B[sub d][sup 0]-B[sub d][sup 0] mixing has been measured using a sample of 150,000 hadronic Z[sup 0] decays collected by the SLD experiment at the SLC between 1993 and 1995. The analysis identifies the semileptonic decays of B mesons with high (p, p[sub t]) leptons and reconstructs the B meson decay length and charge by vertexing the lepton with a partially reconstructed D meson. Vertex charge is used to enrich the selection of neutral over charged B mesons. This method results in a sample of 581 neutral decays with high charge purity. The B candidate is tagged at production with a combined tag that exploits the large polarized b forward-backward asymmetry in conjunction with the opposite hemisphere b jet charge. The final state is tagged by the sign of the high (p, p[sub t]) lepton. From their preliminary analysis the authors find a mass difference between the two B[sub d][sup 0] mass eigenstates of, [Delta]m[sub d]= 0.452[+-] 0.074(stat)[+-] 0.049(syst) ps[sup[minus]1].

The Physics of the B Factories
The Physics of the B Factories

Author: Adrian Bevan

Publisher: Springer

Published: 2015-03-23

Total Pages: 0

ISBN-13: 9783662449905

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This comprehensive work thoroughly introduces and reviews the set of results from Belle and BaBar - after more than two decades of independent and complementary work - all the way from the detectors and the analysis tools used, up to the physics results, and the interpretation of these results. The world’s two giant B Factory collaborations, Belle at KEK and BaBar at SLAC, have successfully completed their main mission to discover and quantify CP violation in the decays of B mesons. CP violation is a necessary requirement to distinguish unambiguously between matter and antimatter. The shared primary objective of the two B Factory experiments was to determine the shape of the so-called unitarity triangle, an abstract triangle representing interactions of quarks, the elementary constituents of matter. The area of the triangle is a measure of the amount of CP violation associated with the weak force. Many other measurements have been performed by the B Factories and are also discussed in this work.