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Observation of a new baryon state in the Λ b 0 π + π − mass spectrum

Journal of High Energy Physics Springer 2020:6 (2020) 136

Authors:

R Aaij, C Abellán Beteta, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, CA Aidala, S Aiola, Z Ajaltouni, S Akar, P Albicocco, J Albrecht, F Alessio, M Alexander, A Alfonso Albero, G Alkhazov, P Alvarez Cartelle, AA Alves, S Amato, Y Amhis, L An, L Anderlini, G Andreassi, M Andreotti

Abstract:

A new baryon state is observed in the Λb0π+π− mass spectrum with high significance using a data sample of pp collisions, collected with the LHCb detector at centre-of-mass energies s = 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The mass and natural width of the new state are measured to be m=6072.3±2.9±0.6±0.2MeV, Γ=72±11±2MeV, where the first uncertainty is statistical and the second systematic. The third uncertainty for the mass is due to imprecise knowledge of the Λb0 baryon mass. The new state is consistent with the first radial excitation of the Λb0 baryon, the Λb(2S)0 resonance. Updated measurements of the masses and the upper limits on the natural widths of the previously observed Λb(5912)0 and Λb(5920)0 states are also reported.
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Search for the lepton flavour violating decay B + → K + μ − τ + using B s 2 ∗ 0 decays

Journal of High Energy Physics Springer 2020:6 (2020) 129

Authors:

R Aaij, C Abellán Beteta, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, CA Aidala, S Aiola, Z Ajaltouni, S Akar, P Albicocco, J Albrecht, F Alessio, M Alexander, A Alfonso Albero, G Alkhazov, P Alvarez Cartelle, AA Alves, S Amato, Y Amhis, L An, L Anderlini, G Andreassi, M Andreotti

Abstract:

A search is presented for the lepton flavour violating decay B+ → K+μ−τ+ using a sample of proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of 9 fb−1. The τ leptons are selected inclusively, primarily via decays with a single charged particle. The four-momentum of the τ lepton is determined by using B+ mesons from Bs2∗0→B+K− decays. No significant excess is observed, and an upper limit is set on the branching fraction ℬ(B+ → K+μ−τ+) < 3.9 × 10−5 at 90 % confidence level. The obtained limit is comparable to the world-best limit.
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Measurements of Absolute Branching Fractions of Fourteen Exclusive Hadronic D Decays to η

Physical Review Letters American Physical Society (APS) 124:24 (2020) 241803

Authors:

M Ablikim, MN Achasov, P Adlarson, S Ahmed, M Albrecht, A Amoroso, Q An, Anita, XH Bai, Y Bai, O Bakina, R Baldini Ferroli, I Balossino, Y Ban, K Begzsuren, JV Bennett, N Berger, M Bertani, D Bettoni, F Bianchi, J Biernat, J Bloms, A Bortone, I Boyko, RA Briere, H Cai, X Cai, A Calcaterra, GF Cao, N Cao, SA Cetin, JF Chang, WL Chang, G Chelkov, DY Chen, G Chen, HS Chen, ML Chen, SJ Chen, XR Chen, YB Chen, WS Cheng, G Cibinetto, F Cossio, XF Cui, HL Dai, JP Dai, XC Dai, A Dbeyssi, RB de Boer, D Dedovich, ZY Deng, A Denig, I Denysenko, M Destefanis, F De Mori, Y Ding, C Dong, J Dong, LY Dong, MY Dong, SX Du, J Fang, SS Fang, Y Fang, R Farinelli, L Fava, F Feldbauer, G Felici, CQ Feng, M Fritsch, CD Fu, Y Fu, XL Gao, Y Gao, Y Gao, YG Gao, I Garzia, EM Gersabeck, A Gilman, K Goetzen, L Gong, WX Gong, W Gradl, M Greco, LM Gu, MH Gu, S Gu, YT Gu, CY Guan, AQ Guo, LB Guo, RP Guo, YP Guo, YP Guo, A Guskov, S Han, TT Han, TZ Han, XQ Hao, FA Harris, KL He, FH Heinsius, T Held, YK Heng, M Himmelreich, T Holtmann, YR Hou, ZL Hou, HM Hu, JF Hu, T Hu, Y Hu, GS Huang, LQ Huang, XT Huang, YP Huang, Z Huang, N Huesken, T Hussain, W Ikegami Andersson, W Imoehl, M Irshad, S Jaeger, S Janchiv, Q Ji, QP Ji, XB Ji, XL Ji, HB Jiang, XS Jiang, XY Jiang, JB Jiao, Z Jiao, S Jin, Y Jin, T Johansson, N Kalantar-Nayestanaki, XS Kang, R Kappert, M Kavatsyuk, BC Ke, IK Keshk, A Khoukaz, P Kiese, R Kiuchi, R Kliemt, L Koch, OB Kolcu, B Kopf, M Kuemmel, M Kuessner, A Kupsc, MG Kurth, W Kühn, JJ Lane, JS Lange, P Larin, L Lavezzi, H Leithoff, M Lellmann, T Lenz, C Li, CH Li, Cheng Li, DM Li, F Li, G Li, HB Li, HJ Li, JL Li, JQ Li, Ke Li, LK Li, Lei Li, PL Li, PR Li, SY Li, WD Li, WG Li, XH Li, XL Li, ZB Li, ZY Li, H Liang, H Liang, YF Liang, YT Liang, LZ Liao, J Libby, CX Lin, B Liu, BJ Liu, CX Liu, D Liu, DY Liu, FH Liu, Fang Liu, Feng Liu, HB Liu, HM Liu, Huanhuan Liu, Huihui Liu, JB Liu, JY Liu, K Liu, KY Liu, Ke Liu, L Liu, Q Liu, SB Liu, Shuai Liu, T Liu, X Liu, YB Liu, ZA Liu, ZQ Liu, YF Long, XC Lou, FX Lu, HJ Lu, JD Lu, JG Lu, XL Lu, Y Lu, YP Lu, CL Luo, MX Luo, PW Luo, T Luo, XL Luo, S Lusso, XR Lyu, F C., H L., L L., M M., Q M., R Q., R T., X N., X X., X Y., Y M., FE Maas, M Maggiora, S Maldaner, S Malde, QA Malik, A Mangoni, YJ Mao, ZP Mao, S Marcello, ZX Meng, JG Messchendorp, G Mezzadri, TJ Min, RE Mitchell, XH Mo, YJ Mo, N Yu Muchnoi, H Muramatsu, S Nakhoul, Y Nefedov, F Nerling, IB Nikolaev, Z Ning, S Nisar, SL Olsen, Q Ouyang, S Pacetti, X Pan, Y Pan, A Pathak, P Patteri, M Pelizaeus, HP Peng, K Peters, J Pettersson, JL Ping, RG Ping, A Pitka, R Poling, V Prasad, H Qi, HR Qi, M Qi, TY Qi, TY Qi, S Qian, W-B Qian, Z Qian, CF Qiao, LQ Qin, XP Qin, XS Qin, ZH Qin, JF Qiu, SQ Qu, KH Rashid, K Ravindran, CF Redmer, A Rivetti, V Rodin, M Rolo, G Rong, Ch Rosner, M Rump, A Sarantsev, Y Schelhaas, C Schnier, K Schoenning, DC Shan, W Shan, XY Shan, M Shao, CP Shen, PX Shen, XY Shen, HC Shi, RS Shi, X Shi, XD Shi, JJ Song, QQ Song, WM Song, YX Song, S Sosio, S Spataro, FF Sui, GX Sun, JF Sun, L Sun, SS Sun, T Sun, WY Sun, YJ Sun, YK Sun, YZ Sun, ZT Sun, YH Tan, YX Tan, CJ Tang, GY Tang, J Tang, V Thoren, B Tsednee, I Uman, B Wang, BL Wang, CW Wang, DY Wang, HP Wang, K Wang, LL Wang, M Wang, MZ Wang, Meng Wang, WH Wang, WP Wang, X Wang, XF Wang, XL Wang, Y Wang, Y Wang, YD Wang, YF Wang, YQ Wang, Z Wang, ZY Wang, Ziyi Wang, Zongyuan Wang, DH Wei, P Weidenkaff, F Weidner, SP Wen, DJ White, U Wiedner, G Wilkinson, M Wolke, L Wollenberg, JF Wu, LH Wu, LJ Wu, X Wu, Z Wu, L Xia, H Xiao, SY Xiao, YJ Xiao, ZJ Xiao, XH Xie, YG Xie, YH Xie, TY Xing, XA Xiong, GF Xu, JJ Xu, QJ Xu, W Xu, XP Xu, F Yan, L Yan, L Yan, WB Yan, WC Yan, Xu Yan, HJ Yang, HX Yang, L Yang, RX Yang, SL Yang, YH Yang, YX Yang, Yifan Yang, Zhi Yang, M Ye, MH Ye, JH Yin, ZY You, BX Yu, CX Yu, G Yu, JS Yu, T Yu, CZ Yuan, W Yuan, XQ Yuan, Y Yuan, ZY Yuan, CX Yue, A Yuncu, AA Zafar, Y Zeng, BX Zhang, Guangyi Zhang, HH Zhang, HY Zhang, JL Zhang, JQ Zhang, JW Zhang, JY Zhang, JZ Zhang, Jianyu Zhang, Jiawei Zhang, L Zhang, Lei Zhang, S Zhang, SF Zhang, TJ Zhang, XY Zhang, Y Zhang, YH Zhang, YT Zhang, Yan Zhang, Yao Zhang, Yi Zhang, ZH Zhang, ZY Zhang, G Zhao, J Zhao, JY Zhao, JZ Zhao, Lei Zhao, Ling Zhao, MG Zhao, Q Zhao, SJ Zhao, YB Zhao, YX Zhao, ZG Zhao, A Zhemchugov, B Zheng, JP Zheng, Y Zheng, YH Zheng, B Zhong, C Zhong, LP Zhou, Q Zhou, X Zhou, XK Zhou, XR Zhou, AN Zhu, J Zhu, K Zhu, KJ Zhu, SH Zhu, WJ Zhu, XL Zhu, YC Zhu, ZA Zhu, BS Zou, JH Zou
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Study of Open-Charm Decays and Radiative Transitions of the X(3872)

Physical Review Letters American Physical Society (APS) 124:24 (2020) 242001

Authors:

M Ablikim, MN Achasov, P Adlarson, S Ahmed, M Albrecht, A Amoroso, Q An, Anita, Y Bai, O Bakina, R Baldini Ferroli, I Balossino, Y Ban, K Begzsuren, JV Bennett, N Berger, M Bertani, D Bettoni, F Bianchi, J Biernat, J Bloms, A Bortone, I Boyko, RA Briere, H Cai, X Cai, A Calcaterra, GF Cao, N Cao, SA Cetin, JF Chang, WL Chang, G Chelkov, DY Chen, G Chen, HS Chen, ML Chen, SJ Chen, XR Chen, YB Chen, W Cheng, G Cibinetto, F Cossio, XF Cui, HL Dai, JP Dai, XC Dai, A Dbeyssi, RB de Boer, D Dedovich, ZY Deng, A Denig, I Denysenko, M Destefanis, F De Mori, Y Ding, C Dong, J Dong, LY Dong, MY Dong, SX Du, J Fang, SS Fang, Y Fang, R Farinelli, L Fava, F Feldbauer, G Felici, CQ Feng, M Fritsch, CD Fu, Y Fu, XL Gao, Y Gao, Y Gao, YG Gao, I Garzia, EM Gersabeck, A Gilman, K Goetzen, L Gong, WX Gong, W Gradl, M Greco, LM Gu, MH Gu, S Gu, YT Gu, CY Guan, AQ Guo, LB Guo, RP Guo, YP Guo, A Guskov, S Han, TT Han, TZ Han, XQ Hao, FA Harris, KL He, FH Heinsius, T Held, YK Heng, M Himmelreich, T Holtmann, YR Hou, ZL Hou, HM Hu, JF Hu, T Hu, Y Hu, GS Huang, LQ Huang, XT Huang, N Huesken, T Hussain, W Ikegami Andersson, W Imoehl, M Irshad, S Jaeger, S Janchiv, Q Ji, QP Ji, XB Ji, XL Ji, HB Jiang, XS Jiang, XY Jiang, JB Jiao, Z Jiao, S Jin, Y Jin, T Johansson, N Kalantar-Nayestanaki, XS Kang, R Kappert, M Kavatsyuk, BC Ke, IK Keshk, A Khoukaz, P Kiese, R Kiuchi, R Kliemt, L Koch, OB Kolcu, B Kopf, M Kuemmel, M Kuessner, A Kupsc, MG Kurth, W Kühn, JJ Lane, JS Lange, P Larin, L Lavezzi, H Leithoff, M Lellmann, T Lenz, C Li, CH Li, Cheng Li, DM Li, F Li, G Li, HB Li, HJ Li, JL Li, JQ Li, Ke Li, LK Li, Lei Li, PL Li, PR Li, WD Li, WG Li, XH Li, XL Li, ZB Li, ZY Li, H Liang, H Liang, YF Liang, YT Liang, LZ Liao, J Libby, CX Lin, B Liu, BJ Liu, CX Liu, D Liu, DY Liu, FH Liu, Fang Liu, Feng Liu, HB Liu, HM Liu, Huanhuan Liu, Huihui Liu, JB Liu, JY Liu, K Liu, KY Liu, Ke Liu, L Liu, LY Liu, Q Liu, SB Liu, T Liu, X Liu, YB Liu, ZA Liu, ZQ Liu, YF Long, XC Lou, HJ Lu, JD Lu, JG Lu, XL Lu, Y Lu, YP Lu, CL Luo, MX Luo, PW Luo, T Luo, XL Luo, S Lusso, XR Lyu, F C., H L., L L., M M., Q M., R Q., R T., X N., X X., X Y., Y M., FE Maas, M Maggiora, S Maldaner, S Malde, QA Malik, A Mangoni, YJ Mao, ZP Mao, S Marcello, ZX Meng, JG Messchendorp, G Mezzadri, TJ Min, RE Mitchell, XH Mo, YJ Mo, N Yu Muchnoi, H Muramatsu, S Nakhoul, Y Nefedov, F Nerling, IB Nikolaev, Z Ning, S Nisar, SL Olsen, Q Ouyang, S Pacetti, Y Pan, Y Pan, M Papenbrock, A Pathak, P Patteri, M Pelizaeus, HP Peng, K Peters, J Pettersson, JL Ping, RG Ping, A Pitka, R Poling, V Prasad, H Qi, M Qi, TY Qi, S Qian, W-B Qian, CF Qiao, LQ Qin, XP Qin, XS Qin, ZH Qin, JF Qiu, SQ Qu, KH Rashid, K Ravindran, CF Redmer, A Rivetti, V Rodin, M Rolo, G Rong, Ch Rosner, M Rump, A Sarantsev, M Savrié, Y Schelhaas, C Schnier, K Schoenning, W Shan, XY Shan, M Shao, CP Shen, PX Shen, XY Shen, HC Shi, RS Shi, X Shi, XD Shi, JJ Song, QQ Song, YX Song, S Sosio, S Spataro, FF Sui, GX Sun, JF Sun, L Sun, SS Sun, T Sun, WY Sun, YJ Sun, YK Sun, YZ Sun, ZT Sun, YX Tan, CJ Tang, GY Tang, V Thoren, B Tsednee, I Uman, B Wang, BL Wang, CW Wang, DY Wang, HP Wang, K Wang, LL Wang, M Wang, MZ Wang, Meng Wang, WP Wang, X Wang, XF Wang, XL Wang, Y Wang, Y Wang, YD Wang, YF Wang, YQ Wang, Z Wang, ZY Wang, Ziyi Wang, Zongyuan Wang, T Weber, DH Wei, P Weidenkaff, F Weidner, HW Wen, SP Wen, DJ White, U Wiedner, G Wilkinson, M Wolke, L Wollenberg, JF Wu, LH Wu, LJ Wu, X Wu, Z Wu, L Xia, H Xiao, SY Xiao, YJ Xiao, ZJ Xiao, YG Xie, YH Xie, TY Xing, XA Xiong, GF Xu, JJ Xu, QJ Xu, W Xu, XP Xu, L Yan, WB Yan, WC Yan, WC Yan, HJ Yang, HX Yang, L Yang, RX Yang, SL Yang, YH Yang, YX Yang, Yifan Yang, Zhi Yang, M Ye, MH Ye, JH Yin, ZY You, BX Yu, CX Yu, G Yu, JS Yu, T Yu, CZ Yuan, W Yuan, XQ Yuan, Y Yuan, CX Yue, A Yuncu, AA Zafar, Y Zeng, BX Zhang, Guangyi Zhang, HH Zhang, HY Zhang, JL Zhang, JQ Zhang, JW Zhang, JY Zhang, JZ Zhang, Jianyu Zhang, Jiawei Zhang, L Zhang, Lei Zhang, S Zhang, SF Zhang, TJ Zhang, XY Zhang, Y Zhang, YH Zhang, YT Zhang, Yan Zhang, Yao Zhang, Yi Zhang, ZH Zhang, ZY Zhang, G Zhao, J Zhao, JY Zhao, JZ Zhao, Lei Zhao, Ling Zhao, MG Zhao, Q Zhao, SJ Zhao, YB Zhao, YX Zhao Zhao, ZG Zhao, A Zhemchugov, B Zheng, JP Zheng, Y Zheng, YH Zheng, B Zhong, C Zhong, LP Zhou, Q Zhou, X Zhou, XK Zhou, XR Zhou, AN Zhu, J Zhu, K Zhu, KJ Zhu, SH Zhu, WJ Zhu, XL Zhu, YC Zhu, ZA Zhu, BS Zou, JH Zou
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Measurement of the Λ b 0 → J/ψ Λ angular distribution and the Λ b 0 polarisation in pp collisions

Journal of High Energy Physics Springer 2020:6 (2020) 110

Authors:

R Aaij, C Abellán Beteta, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, CA Aidala, S Aiola, Z Ajaltouni, S Akar, J Albrecht, F Alessio, M Alexander, A Alfonso Albero, G Alkhazov, P Alvarez Cartelle, AA Alves, S Amato, Y Amhis, L An, L Anderlini, G Andreassi, A Andreianov, M Andreotti

Abstract:

This paper presents an analysis of the Λb0→ J/ψΛ angular distribution and the transverse production polarisation of Λb0 baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb−1, collected with the LHCb experiment. The polarisation is determined in a fiducial region of Λb0 transverse momentum and pseudorapidity of 1 < pT< 20 GeV/c and 2 < η < 5, respectively. The data are consistent with Λb0 baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Λ → pπ− decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration.
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