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The Direct Coupling of Light Quarks to Heavy Di-quarks

An, Haipeng and Wise, Mark B. (2019) The Direct Coupling of Light Quarks to Heavy Di-quarks. Physics Letters B, 788 . pp. 131-136. ISSN 0370-2693. doi:10.1016/j.physletb.2018.11.004.

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In the limit m_Q > m_Q v_(rel) > m_Q v_(rel)^2 ≫ Λ_(QCD) hadronic states with two heavy quarks Qshould be describable by a version of HQET where the heavy quark is replaced by a di-quark degree of freedom. In this limit the di-quark is a small (compared with 1/ΛQCD) color anti-triplet, bound primarily by a color Coulomb potential. The excited Coulombic states and color six states are much heavier than the color anti-triplet ground state. The low lying spectrum of hadrons containing two heavy quarks is then determined by the coupling of the light quarks and gluons with momentum of order ΛQCD to this ground state di-quark. In this short paper we calculate the coefficient of leading local operator (S_v^†S_v)(qγ^μv_μq) that couples this color anti-triplet di-quark field S_v (with four-velocity v) directly to the light quarks q in the low energy effective theory. It is O(1/(α_s(m_Qv_(rel))m_Q^2)). While our work is mostly of pedagogical value we make an estimate of the contribution of this operator to the masses of Ξ_(bbq) baryon and T_(QQqq) tetraquark using the non-relativistic constituent quark model.

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Additional Information:© 2018 Published by Elsevier B.V. This is an open access article under the CC BY license ( Funded by SCOAP3. Received 18 September 2018, Accepted 4 November 2018, Available online 6 November 2018. We thank Aneesh Manohar, Tom Mehen, Ira Rothstein, and Mikhail Solon for some useful comments. HA is supported by the Recruitment Program for Young Professionals of the 1000 Talented Plan and the Tsinghua University Initiative Scientific Research Program. MBW is supported by the DOE Grant DE-SC0011632 and the Walter Burke Institute for Theoretical Physics. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Economic Development & Innovation.
Group:Walter Burke Institute for Theoretical Physics
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China 1000-Young Talents PlanUNSPECIFIED
Tsinghua UniversityUNSPECIFIED
Department of Energy (DOE)DE-SC0011632
Walter Burke Institute for Theoretical Physics, CaltechUNSPECIFIED
Industry CanadaUNSPECIFIED
Ontario Ministry of Economic Development and InnovationUNSPECIFIED
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Record Number:CaltechAUTHORS:20180912-092027955
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Official Citation:Haipeng An, Mark B. Wise, The direct coupling of light quarks to heavy di-quarks, Physics Letters B, Volume 788, 2019, Pages 131-136, ISSN 0370-2693, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89556
Deposited By: Joy Painter
Deposited On:12 Sep 2018 18:59
Last Modified:16 Nov 2021 00:36

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