Search for Bottomonium States in Exclusive Radiative gamma(2S) Decays

We search for bottomonium states in gamma(2S) -> (b (b) over bar)gamma decays with an integrated luminosity of 24.7 fb(-1) recorded at the gamma(2S) resonance with the Belle detector at KEK, containing (157.8 +/- 3.6) x 10(6) gamma(2S) events. The (b (b) over bar) system is reconstructed in 26 exclusive hadronic final states composed of charged pions, kaons, protons, and K-0(S) mesons. We find no evidence for the state recently observed around 9975 MeV (X-b (b) over bar) in an analysis based on a data sample of 9.3 x 10(6) gamma(2S) events collected with the CLEO III detector. We set a 90% confidence level upper limit on the branching fraction B[gamma(2S) -> X-b (b) over bar gamma] x Sigma(i) B[X-b (b) over bar -> h(i)] < 4.9 x 10(-6), summed over the exclusive hadronic final states employed in our analysis. This result is an order of magnitude smaller than the measurement reported with CLEO data. We also set an upper limit for the eta(b)(1S) state of B[gamma(2S) -> eta(b)(1S)gamma] x Sigma B-i[eta(b)(1S) -> h(i)] < 3.7 x 10(-6).

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Tagir Aushev, Dipanwita Dutta, Donghyun Kim, Ji Hyun Kim, Jing Li, Yiming Li, Zhen Liu, Olivier Schneider, Mingkui Wang, Xiao Wang
Amer Physical Soc, 2013
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https://infoscience.epfl.ch/record/190217?ln=fr

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Luminosité

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Radioactivité β

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Measurement of the CKM angle gamma from a combination of B-+/- -> Dh(+/-) analyses

Vladislav Balagura, Aurelio Bay, Marc-Olivier Bettler, Frédéric Blanc, Joël Bressieux, Peter Clarke, Victor Coco, Greig Alan Cowan, Adam Davis, Michel De Cian, Hans Dijkstra, Frédéric Guillaume Dupertuis, Vincent Fave, Christoph Frei, Guido Haefeli, Plamen Hristov Hopchev, Pierre Jaton, Anne Keune, Ilya Komarov, Yiming Li, Johan Luisier, Maurizio Martinelli, Raluca Anca Muresan, Bastien Luca Muster, Tatsuya Nakada, Matthew Needham, Niko Neufeld, Cédric Potterat, Jessica Prisciandaro, Barinjaka Rakotomiaramanana, Gerhard Raven, Julien Rouvinet, Christophe Salzmann, Olivier Schneider, Liang Sun, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Jian Wang, Jean Wicht, Songmei Wu, Yi Zhang, Lei Zhang

A combination of three LHCb measurements of the CKM angle gamma is presented. The decays B-+/- -> DK +/- and B-+/- -> D pi(+/-) are used, where D denotes an admixture of D-0 and (D) over bar (0) mesons, decaying into K+K-, pi(+)pi(-), K-+/-pi(-/+), K-+/-pi(-/+)pi(+/-)pi(-/+), or K-S(0)pi(+)pi(-) final states. All measurements use a dataset corresponding to 1.0 fb-1 of integrated luminosity. Combining results from B-+/- -> DK +/- Dill decays alone a best-fit value of gamma = 72.0 degrees is found, and confidence intervals are set gamma is an element of [56.4, 86.7]degrees at 68% CL, gamma is an element of [42.6, 99.6]degrees at 95% CL. The best-fit value of gamma found from a combination of results from B-+/- -> D pi(+/-) decays alone, is gamma = 18.9 degrees, and the confidence intervals gamma is an element of [7.4, 99.2]degrees boolean OR [167.9, 176.4]degrees at 68% CL are set, without constraint at 95% CL The combination of results from B1 DKI and B -> DTC decays gives a best-fit value of y = 72.6 degrees and the confidence intervals gamma is an element of [55.4, 82.3]degrees at 68% CL, gamma is an element of [40.2, 92.7]degrees at 95% CL are set. All values are expressed modulo 180 degrees, and are obtained taking into account the effect of D-0-(D) over bar (0) mixing. (C) 2013 CERN. Published by Elsevier B.V. All rights reserved.

Elsevier Science Bv2013

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Search for the B -> Y(4260)K, Y(4260) -> J/psi pi(+)pi(-) decays

Tagir Aushev, Sun Hee Kim, Donghyun Kim, Ji Hyun Kim, Lei Li, Yiming Li, Olivier Schneider, Mingkui Wang, Xiao Wang

We report the results of a search for the B -> Y(4260)K, Y(4260) -> J/psi pi(+)pi thorn p-decays. This study is based on a data sample corresponding to an integrated luminosity of 711 fb(-1), collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We investigate the J/psi pi(+)pi(-) thorn p-invariant mass distribution in the range 4.0 to 4.6 GeV/c(2) using both B+ -> J/psi pi(+)pi K--(+) and B-0 -> J/psi pi(+)pi K--(S)0 decays. We find excesses of events above the background levels, with significances of 2.1 and 0.9 standard deviations for charged and neutral B -> Y(4260)K decays, respectively, taking into account the systematic uncertainties. These correspond to upper limits on the product of branching fractions, B(B+ -> Y(4260)K+) x B(Y(4260) -> J/psi pi(+)pi(-)) < 1.4 x 10(-5) and B(B-0 -> Y(4260)K-0) x B(Y(4260) -> J/psi pi(+)pi(-)) < 1.7 x 10(-5) at the 90% confidence level.

2019

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Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at root s=13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Chunhui Chen, Yixing Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Bertrand François, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Doohyun Kim, Ji Hyun Kim, Donghyun Kim, Ajay Kumar, Sanjeev Kumar, Vineet Kumar, Ekaterina Kuznetsova, Federica Legger, Jing Li, Yiming Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Jessica Prisciandaro, Quentin Python, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Ashish Sharma, Varun Sharma, Wei Shi, Kun Shi, Muhammad Shoaib, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Zheng Wang, Xiao Wang, Hui Wang, Qian Wang, Siyuan Wang, Jian Wang, Yi Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang, Kai Yi, Yi Zhang, Hua Zhang, Jian Zhao

A search is performed for the rare decay W-+/--> pi(+/-)gamma in proton-proton collisions at root s = 13 TeV. Data corresponding to an integrated luminosity of 137 fb(-1) were collected during 2016 to 2018 with the CMS detector. This analysis exploits a novel search strategy based on W boson production in top quark pair events. An inclusive search for the W-+/--> pi(+/-)gamma decay is not optimal at the LHC because of the high trigger thresholds. Instead, a trigger selection is exploited in which the W boson originating from one of the top quarks is used to tag the event in a leptonic decay. The W boson emerging from the other top quark is used to search for the W-+/--> pi(+/-)gamma signature. Such decays are characterized by an isolated track pointing to a large energy deposit, and by an isolated photon of large transverse momentum. The presence of b quark jets reduces the background from the hadronization of light-flavor quarks and gluons. The W-+/- -> pi(+/-)gamma decay is not observed. An upper exclusion limit is set to this branching fraction, corresponding to 1.50 x 10(-5) at 95% confidence level, whereas the expected upper exclusion limit is 0.85(-0.29)(+0.52) x 10(-5). (C) 2021 The Author(s). Published by Elsevier B.V.

2021

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