Abstract
The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 < Q 2 < 1000 GeV2 using an integrated luminosity of 354 pb−1. The beauty and charm content in events with at least one jet have been extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of Q 2, Bjorken x, jet trans- verse energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q 2. The running beauty-quark mass, m b at the scale m b , was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be m b (m b ) = 4.07 ± 0.14 (fit) + 0.01− 0.07 (mod.) + 0.05− 0.00 (param.) + 0.08− 0.05 (theo.) GeV.
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ArXiv ePrint: 1405.6915
Supported by the Italian National Institute for Nuclear Physics. (INFN) (1, 2, 5, 23, 24, 26, 29, 30)
Supported by the German Federal Ministry for Education and Research (BMBF), under contract No. 05 H09PDF. (3)
Supported by HIR grant UM.C/625/1/HIR/149 and UMRG grants RU006-2013, RP012A-13AFR and RP012B-13AFR from Universiti Malaya, and ERGS grant ER004-2012A from the Ministry of Education, Malaysia. (6)
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Supported by the Science and Technology Facilities Council, UK. (12, 22, 32)
Supported by the German Federal Ministry for Education and Research (BMBF), under contract No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG). (13)
Supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research. (14, 19, 25, 28)
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Supported by RF Presidential grant N 3042.2014.2 for the Leading Scientific Schools and by the Russian Ministry of Education and Science through its grant for Scientific Research on High Energy Physics. (20)
Supported by the Israel Science Foundation. (27)
Also funded by Max Planck Institute for Physics, Munich, Germany. (R. Aggarwal, P. Kaur)
Also funded by Max Planck Institute for Physics, Munich, Germany. (I. Singh)
Partially supported by the Polish National Science Centre projects DEC-2011/01/B/ST2/03643 and DEC-2011/03/B/ST2/00220. (W. Slominski)
Supported by the Alexander von Humboldt Foundation. (V. Myronenko, O. Turkot, K. Wichmann)
Alexander von Humboldt Professor. (B. Foster)
Supported by DESY, Germany. (V. Aushev, Y. Aushev, V. Bokhonov, N. Zhmak)
Member of National Technical University of Ukraine, Kyiv Polytechnic Institute, Kyiv, Ukraine. (Y. Aushev, A. Iudin, R. Shevchenko)
Member of National University of Kyiv - Mohyla Academy, Kyiv, Ukraine. (N. Kovalchuk, O. Shkola, A. Trofymov, N. Zakharchuk).
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Also supported by DESY. (M. Wing)
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The ZEUS collaboration., Abramowicz, H., Abt, I. et al. Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass. J. High Energ. Phys. 2014, 127 (2014). https://doi.org/10.1007/JHEP09(2014)127
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DOI: https://doi.org/10.1007/JHEP09(2014)127