Measurement of Branching Fractions and Rate Asymmetries in the Rare Decays B{u2192}K(*)l+l-. PDF Download
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Languages : en
Pages : 16
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In a sample of 471×106 BB¯ events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B→K(*)l+l-, where l+l- is either e+e- or ?+?-. We report results on partial branching fractions and isospin asymmetries in seven bins of dilepton mass-squared. We further present CP and lepton-flavor asymmetries for dilepton masses below and above the J/? resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.
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Languages : en
Pages : 16
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Book Description
In a sample of 471×106 BB¯ events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B→K(*)l+l-, where l+l- is either e+e- or ?+?-. We report results on partial branching fractions and isospin asymmetries in seven bins of dilepton mass-squared. We further present CP and lepton-flavor asymmetries for dilepton masses below and above the J/? resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.
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Languages : en
Pages : 16
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![Measurements of Branching Fractions, Rate Asymmetries, and Angular Distributions in the Rare Decays B -] Kl+l- and B -] K*l+ L- PDF](https://books.google.com/books/content/images/frontcover/-NeEAQAACAAJ?fife=w80-h100)
Author: B. Aubert
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Languages : en
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We present measurements of the flavor-changing neutral current decays B {yields} K{ell}{sup +}{ell}{sup -} and B {yields} K*{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either an e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -} pair. The data sample comprises 229 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. Flavor-changing neutral current decays are highly suppressed in the Standard Model and their predicted properties could be significantly modified by new physics at the electroweak scale. We measure the branching fractions {Beta}(B {yields} K{ell}{sup +}{ell}{sup -}) = (0.34 {+-} 0.07 {+-} 0.02) x 10{sup -6}, {Beta}(B {yields} K*{ell}{sup +}{ell}{sup -}) = (0.78{sub -0.17}{sup +0.19} {+-} 0.11) x 10{sup -6}, the direct CP asymmetries of these decays, and the relative abundances of decays to electrons and muons. For two regions in {ell}{sup +}{ell}{sup -} mass, above and below m{sub J/{psi}}, we measure partial branching fractions and the forward-backward angular asymmetry of the lepton pair. In these same regions we also measure the K* longitudinal polarization in B {yields} K*{ell}{sup +}{ell}{sup -} decays. Upper limits are obtained for the lepton flavor-violating decays B {yields} Ke{mu} and B {yields} K*e{mu}. All measurements are consistent with Standard Model expectations.
![Measurements of Rates, Asymmetries, and Angular Distributions in B -] K L+ L- and B -] K* L+ L- Decays PDF](https://books.google.com/books/content/images/frontcover/IyvCjwEACAAJ?fife=w80-h100)
Author: Jonathan Hollar
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Languages : en
Pages : 124
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This dissertation describes studies of the rare decays B{sub d} {yields} K{ell}{sup +}{ell}{sup -} and B{sub d} {yields} K*{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either an e{sup +}e{sup -} or a {mu}{sup +}{mu}{sup -} pair. These decays are highly suppressed in the Standard Model, and could be strongly affected by physics beyond the Standard Model. The authors measure the total branching fractions {Beta}(B{sub d} {yields} K{ell}{sup +}{ell}{sup -}) = (0.34 {+-} 0.07 {+-} 0.03) x 10{sup -6}, {Beta}(B{sub d} {yields} K*{ell}{sup +}{ell}{sup -}) = (0.78{sub -0.17}{sup +0.19} {+-} 0.12) x 10{sup -6}. In addition, they measure the partial branching fractions, relative abundance of muons to electrons, direct CP asymmetry, dilepton forward-backward asymmetry, and longitudinal polarization of the K* in these modes. They also search for the lepton flavor-violating decays B{sub d} {yields} Ke{sup {+-}}{mu}{sup {-+}} and B{sub d} {yields} K*e{sup {+-}}{mu}{sup {-+}}. The measurements were performed at the SLAC PEP II storage ring running at the {Upsilon}(4S) resonance.
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Languages : en
Pages : 15
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The authors report the measurement of the branching fractions of the rare decays B° → D{sub s}{sup (*)+}?−, B° → D{sub s}{sup (*)+}?−, and B° → D{sub s}{sup (*)-} K{sup (*)+} in a sample of 381 x 106?(4S) decays into B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy ee− storage ring. They present evidence for the decay B° → D{sub s}− K*+ and the vector-vector decays B° → D{sub s}{sup *+}?− and B° → D{sub s}{sup *-} K{sup *+}, as well as the first measurement of the vector meson polarization in these decays. They also determine the ratios of the CM-suppressed to CKM-favored amplitudes r(D{sup (*)}?) and r(D{sup (*)}?) in decays B° → D{sup (*)}{sup {+-}}?{sup {-+}} and B° → D{sup (*)}{sup {+-}}?{sup {-+}}, and comment on the prospects for measuring the Cp observable sin(2? +?).
![Branching ratio and direct CP-violating rate asymmetry of the rare decays B → K*[gamma] and B → [rho gamma]1 PDF](https://books.google.com/books/content/images/frontcover/U32PzQEACAAJ?fife=w80-h100)
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Languages : en
Pages : 21
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![Branching ratio and direct CP-violating rate asymmetry of the rare decays B → K*γ [K gamma] and B → ργ [rhogamma] PDF](https://books.google.com/books/content/images/frontcover/1CPGzQEACAAJ?fife=w80-h100)
Author: Christoph Greub
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Languages : de
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Languages : en
Pages : 217
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The standard model has been highly successful at describing current experimental data. However, extensions of the standard model predict particles that have masses at energy scales that are above the electroweak scale. The flavor-changing neutral current processes of the B meson are sensitive to the influences of these new physics contributions. These processes proceed through loop diagrams, thus allowing new physics to enter at the same order as the standard model. New physics may contribute to the enhancement or suppression of rate asymmetries or the decay rates of these processes. The transition B 2!V? (V = K*(892),?(770),?(782),?(1020)) represents radiative decays of the B meson that proceed through penguin processes. Hadronic uncertainties limit the theoretical accuracy of the prediction of the branching fractions. However, uncertainties, both theoretical and experimental, are much reduced when considering quantities involving ratios of branching fractions, such as CP or isospin asymmetries. The most dominant exclusive radiative b 2!s transition is B 2!K*?. We present the best measurements of the branching fractions, direct CP, and isospin asymmetries of B 2!K*?. The analogous b 2!d transitions are B 2!?? and B 2!??, which are suppressed by a factor of.
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Languages : en
Pages : 7
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The authors present measurements of branching fractions and charge asymmetries for the decays B 2![eta]K*, where K8 indicates a spin 0, 1, or 2 K [pi] system. The data sample corresponds to 344 x 106 B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy ee− collider at SLAC. They measure the branching fractions (in units of 10−6): [Beta](B° 2![eta]K*°(892)) = 16.5 ± 1.1 ± 0.8, [Beta](B 2![eta]K*+(892)) = 18.9 ± 1.8 ± 1.3, [Beta](B° 2*0°) = 11.0 ± 1.6 ± 1.5, [Beta](B+ 20*+) = 18.2 ± 2.6 ± 2.6, [Beta](B° 2![eta]K*2°(1430)) = 9.6 ± 1.8 ± 1.1, and [Beta](B+ 2![eta]K*2+(1430)) = 9.1 ± 2.7 ± 1.4. They also determine the charge asymmetries for all decay modes.
![Measurements of Branching Fractions and CP-Violating Asymmetries in B-Meson Decays to the Charmless Two-Body States K[sup 0]pi+, K-bar[sup 0]K[sup +], and K[sup 0]K-bar[sup 0]. PDF](https://books.google.com/books/content/images/frontcover/t_n-jwEACAAJ?fife=w80-h100)
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Languages : en
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The authors present preliminary measurements of the branching fraction and the CP-violating charge asymmetry in the B[sup +] --> K[sup 0][pi][sup +] decay, and a preliminary measurement of the branching fraction of the B[sup 0] --> K[sup 0][bar K][sup 0] decay. No evidence of direct CP violation in the B[sup +] --> K[sup 0][pi][sup +] mode is observed. The B[sup 0] --> K[sup 0][bar K][sup 0] measurement constitutes the first observation of this decay channel: the probability of obtaining the result assuming the null-signal hypothesis is 3.4 x 10[sup -6]. The authors have also searched for the B[sup +] --> [bar K][sup 0]K[sup +] decay and set an upper limit on its branching fraction at 2.35 x 10[sup -6] at the 90% C.L. The branching-fraction measurements reported here are consistent with previous measurements of the same quantities, but are extracted from a data sample larger by a factor of 2.6.
