The observation of the decay Xi(-)(b)-> J/psi Lambda K- is reported, using a data sample corresponding to an integrated luminosity of 3 fb(-1), collected by the LHCb detector in pp collisions at centre-of-mass energies of 7 and 8 TeV. The production rate of Xi(-)(b) baryons detected in the decay Xi(-)(b) -> J/psi Lambda K- is measured relative to that of Lambda(0)(b) baryons using the decay Lambda(0)(b) -> J/psi Lambda. Integrated over the b-baryon transverse momentum p(T) < 25 GeV/c and rapidity 2.0 < y < 4.5, the measured ratio is f Xi(-)(b/) f Lambda(0)(b) B(Xi(-)(b)-> J/psi Lambda K-) / B(Lambda(0)(b)-> J/psi Lambda) = (4.19 +/- 0.29 (stat) +/- 0.15 (syst)) x 10(-2), where f(Xi)(b)(-) band f(Lambda)(b)(0)are the fragmentation fractions of b ->Xi(-)(b)and b ->Lambda(0)(b)transitions, and ss represents the branching fraction of the corresponding b- baryon decay. The mass difference between Xi(-)(b) and Lambda(0)(b) baryons is measured to be M(Xi(-)(b))-M(Lambda(0)(b)) = 177.08 +/- 0.47 (stat) +/- 0.16 (syst) MeV/c(2). (C) 2017 The Author(s). Published by Elsevier B.V.
Matthias Finger, Qian Wang, Yiming Li, Varun Sharma, Konstantin Androsov, Jan Steggemann, Xin Chen, Rakesh Chawla, Matteo Galli, Jian Wang, João Miguel das Neves Duarte, Tagir Aushev, Matthias Wolf, Yi Zhang, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Siyuan Wang, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Sun Hee Kim, Kun Shi, Abhisek Datta, Federica Legger, Gabriele Grosso, Anna Mascellani, Ji Hyun Kim, Donghyun Kim, Zheng Wang, Sanjeev Kumar, Wei Li, Yong Yang, Ajay Kumar, Ashish Sharma, Georgios Anagnostou, Joao Varela, Csaba Hajdu, Muhammad Ahmad, Ioannis Evangelou, Milos Dordevic, Meng Xiao, Sourav Sen, Xiao Wang, Kai Yi, Jing Li, Rajat Gupta, Hui Wang, Seungkyu Ha, Pratyush Das, Anton Petrov, Xin Sun, Valérie Scheurer, Muhammad Ansar Iqbal
Matthias Finger, Qian Wang, Yiming Li, Varun Sharma, Konstantin Androsov, Jan Steggemann, Xin Chen, Rakesh Chawla, Matteo Galli, Jian Wang, João Miguel das Neves Duarte, Tagir Aushev, Matthias Wolf, Yi Zhang, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Leonardo Cristella, Siyuan Wang, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Sun Hee Kim, Davide Di Croce, Kun Shi, Abhisek Datta, Jian Zhao, Federica Legger, Gabriele Grosso, Anna Mascellani, Ji Hyun Kim, Donghyun Kim, Zheng Wang, Sanjeev Kumar, Wei Li, Yong Yang, Ajay Kumar, Ashish Sharma, Georgios Anagnostou, Joao Varela, Csaba Hajdu, Muhammad Ahmad, Ekaterina Kuznetsova, Ioannis Evangelou, Muhammad Shoaib, Milos Dordevic, Meng Xiao, Sourav Sen, Xiao Wang, Kai Yi, Jing Li, Rajat Gupta, Muhammad Waqas, Hui Wang, Seungkyu Ha, Pratyush Das, Miao Hu, Anton Petrov, Xin Sun, Valérie Scheurer, Muhammad Ansar Iqbal, Lukas Layer