NLO QCD Corrections in Inclusive Bc* Production
Discover the NLO QCD corrections in inclusive Bc* production within Z0 decays, including background information on Bc mesons, direct and indirect production methods, motivation behind the research, calculation divergences, and IR in one-loop diagrams. Explore the latest advancements and theoretical discussions in this field.
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The NLO QCD Corrections to Inclusive Bc*Production in Z0Decays Jun Jiang 2015.1.10
Outline Background NLO Calculation Results &Discussion Summary
Background BcMeson Bc meson was discovered by CDF in 1998. Phys. Rev. Lett. 81, 2432 (1998); Phys. Rev. D 58, 112004 (1998). Mass & lifetime: [PDG Collaboration], Chin. Phys. C 38, 090001 (2014). = 6.2756 0.0011 ( ) = , M B GeV c ( ) 0.500 0.013 . B ps c Excited states Bc(2S) was observed by ATLAS recently. = 6842 4 5 ( (2 )) S M B MeV c
Background Direct production Various investigations by C. H. Chang, Y. Q. Chen, J. X. Wang, C. F. Qiao, X. G. Wu, E. Braaten et al. P-Wave Phys. Rev. D 70, 114019 (2004). Color-octet Phys. Rev. D 71, 074012 (2005). Intrinsic heavy quark mechanism Phys. Rev. D 72, 114009 (2005). Fragmentation Phys. Rev. D 46, 3845 (1992) [Erratum-ibid. D 50, 6013 (1994)]; Phys. Rev. D 48, 5049 (1993). BCVEGPY Comput. Phys. Commun. 159, 192 (2004).
Background Indirect production Top decays Leading order(LO): C. F. Qiao, C. S. Li and K. T. Chao, Phys. Rev. D 54, 5606 (1996); C. H. Chang, J. X. Wang and X. G. Wu, Phys. Rev. D 77, 014022 (2008); X. G. Wu, Phys. Lett. B 671, 318 (2009). Next-to-leading order(NLO): P. Sun, L. P. Sun and C. F. Qiao, Phys. Rev. D 81, 114035 (2010). W decays C. F. Qiao et al. Eur. Phys. J. C 71, 1766 (2011); X. G. Wu, Phys. Rev. D 85, 014032 (2012). LO: Z0decays LO calculation by C. H. Chang etc., V. V. Kiselev etc. NLO, Bc[1S0]: C. F. Qiao, L. P. Sun and R. L. Zhu, JHEP 1108, 131 (2011). NLO, Bc*[3S1]: J. Jiang, L. B. Chen and C. F. Qiao, arXiv: 1501.00338, submitting to PRD.
Background Motivation Z0platform 0 ( ) 34 Z nb LHC Phys. Rev. Lett. 112, 191802 (2014). 0 ( ) 30 Z nb ILC at GigaZ mode Phys. Lett. B 486, 125 (2000). 34 2 1 8 1 9 0 10 10 10 . L cm s nb Z events Large correction + + 0 1 [ ] Z B S c b 0 c = = = 2 , 1.08, NLO = m K b LO = / 2, 1.59, m K Z
NLO Calculation Divergences + 0 * 3 [ c ] Z B S X 1 UV IR Coulomb Threshold expansion technique Counter terms One-Loop Diagrams M. Beneke and V. A. Smirnov, Nucl. Phys. B 522, 321 (1998). Counter terms Real Correction
NLO Calculation IR in one-loop diagrams IR finite + + + +
NLO Calculation IR in real correction B. W. Harris and J. F. Owens, Phys. Rev. D 65, 094032 (2002).
NLO Calculation Axial-vector current J. G. Korner, D. Kreimer and K. Schilcher, Z. Phys. C 54, 503 (1992). No contribution. No contribution.
Results & Discussion Decay width versus
Results & Discussion K-factor With increasing, K-factor grows, yet it grows slower at high region. With increasing, ( ) decreases, yet it decreases slower at high region. ( ) is much more sensitive to mcthan mb.
Results & Discussion Uncertainties
Results & Discussion Production rate At =2mb, Total production rate, = 1.22. K total At =mZ/2, = 1.67. K total
Summary In arXiv:1501.00338, we calculate the QCD NLO Corrections to inclusive Bc* production in Z0decays. When running from 2mbto mZ/2, K-factor gro -ws from 1.33 to 1.73. Parameter of mchas a quite large influence on .
