DOCSLIB.ORG

Theoretical Interpretation of the XYZ Mesons

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Theoretical Interpretation of the XYZ Mesons Theoretical Interpretation of the XYZ Mesons Eric Braaten Ohio State University 1 Theoretical Interpretation of the XYZ Mesons Introduction New results on XYZ states ... ... from hadron collider experiments Sebastien Neubert ... from e+e− collider experiments Changzheng Yuan 2 Theoretical Interpretation of the XYZ Mesons Outline Models for XYZ Mesons quarkonium quarkonium hybrids quarkonium tetraquarks QCD Theory Lattice QCD Lattice NRQCD Born-Oppenheimer approximation 3 _ Discovery of Tetraquark bb Mesons! + + Zb (10610), Zb (10650) Belle 2011 + + both decay into Υ(nS) π and hb(nP)_ π _ ⟹ constituents are b b u d 120 ) (e) 2 100 80 Zb 60 Zb′ 40 20 (Events/4 MeV/c 0 10.58 10.62 10.66 10.70 10.74 2 M(Y(3S))max, (GeV/c ) 4 _ Discovery of Tetraquark cc Mesons! + Zc (3900) BESIII April_ _2013 decays into J/ψ π+ ⟹ constituents are c c u d Data 100 2 Zc Total fit Background fit 80 PHSP MC Sideband 60 40 20 Events / 0.01 GeV/c 0 3.7 3.8 3.9 4.0 ± 2 Mmax( J/) (GeV/c ) + Zc (4020) BESIII June 2013_ _ + decays into hc(nP) π ⟹ constituents are c c u d 5 _ _ New cc Mesons above DD threshold TABLE I: State M (MeV) Γ(MeV) J PC Decay modes 1st observation neutral cc¯ mesons X(3823) 3823.1 1.9 < 24 ?? χ γ Belle 2013 ± − c1 X(3872) 3871.68 0.17 < 1.21++ J/ ⇡+⇡ , J/ ⇡+⇡ ⇡0 Belle 2003 ± − − D0D¯ 0⇡0, D0D¯ 0γ J/ γ, (2S) γ X(3915) 3917.5 1.9 20 50++ J/ !, γγ Belle 2004 ± ± χ (2P ) 3927.2 2.6 24 62++ DD¯, γγ Belle 2005 c2 ± ± +9 +27 ?+ ¯ X(3940) 3942 8 37 17 ? D⇤D Belle 2007 − − G(3900) 3943 21 52 11 1 DD¯ BABAR 2007 ± ± −− 15 neutral +121 + Y (4008) 4008 49 226 97 1−− J/ ⇡ ⇡− Belle 2007 _ − ± +11 ?+ Y (4140) 4144.5 2.6 15 7 ? J/ φ CDF 2009 ± − cc mesons +29 +113 ?+ ¯ X(4160) 4156 25 139 65 ? D⇤D⇤ Belle 2007 − − +8 + 0 0 Y (4260) 4263 9 95 14 1−− J/ ⇡ ⇡−, J/ ⇡ ⇡ BABAR 2005 − ± Zc(3900) ⇡ +8.4 +22 ?+ Y (4274) 4274.4 6.7 32 15 ? J/ φ CDF 2010 − − +4.6 +18.4 ++ X(4350) 4350.6 5.1 13.3 10.0 0/2 J/ φ, γγ Belle 2009 − − Y (4360) 4361 13 74 18 1 (2S) ⇡+⇡ BABAR 2007 ± ± −− − +9 +41 + X(4630) 4634 11 92 32 1−− ⇤c ⇤c− Belle 2007 − − Y (4660) 4664 12 48 15 1 (2S) ⇡+⇡ Belle 2007 ± ± −− − charged cc¯ mesons Z+(3900) 3898 5 51 19 ?? J/ ⇡+ BESIII 2013 c ± ± − 5 charged + ? + ¯ Zc (4020) 4021.8 2.75.7 3.6?− hc(1P ) ⇡ , D⇤D⇤ BESIII 2013 _ ± ± + +24 +51 ?+ + Z1 (4050) 4051 43 82 55 ? χc1(1P ) ⇡ Belle 2008 − − cc mesons + +185 +321 ?+ + Z2 (4250) 4248 45 177 72 ? χc1(1P ) ⇡ Belle 2008 − − + +24 +113 + + Z (4430) 4443 18 107 71 1 − (2S) ⇡ Belle 2007 − − 6 1 _ _ New bb Mesons above BB threshold TABLE I: State M (MeV) Γ(MeV) J PC Decay modes 1st observation 1_ neutral neutral b¯b mesons +8.9 + bb meson Yb(10888) 10888.4 3.0 30.7 7.7 1−− ⌥(nS) ⇡ ⇡− Belle 2010 ± − + + Zb (10610) ⇡, Zb (10610) ⇡ charged b¯b mesons 2_ charged Z+(10610) 10607.2 2.0 18.4 2.4 1+ ⌥(nS) ⇡+, h (nP ) ⇡+ Belle 2011 b ± ± − b Z+(10650) 10652.2 1.5 11.5 2.2 1+ ⌥(nS) ⇡+, h (nP ) ⇡+ Belle 2011 bb mesons b ± ± − b _ many unexpected _neutral QQ mesons several charged QQ mesons many of them are narrow a major challenge to our understanding of the QCD spectrum! 7 1 Models for XYZ Mesons _ ● conventional quarkonium QQ _ Q Q ● quarkonium hybrids g _ Q q_ ● quarkonium tetraquarks q Q ● compact tetraquark ● meson molecule ● diquark-onium ● hadro-quarkonium 8 _ Models for XYZ Mesons quarkonium tetraquarks _ ● compact tetraquark Q q_ q Q _ _ ● meson molecule Qq qQ _ _ ● diquark-onium Qq qQ q _ ● hadro-quarkonium QQ _ q ● Born-Oppenheimer tetraquark! arXiv:1305.6905 9 Models for XYZ Mesons _ Conventional Quarkonium Q Q ● well-developed phenomenology based on potential models ● accurate below open-heavy-flavor threshold! how accurate above? ● spin-symmetry multiplets –+ -- S-wave: {0 ,1 } +– ++ P-wave: {1 ,(0,1,2) } –+ -- D-wave: {2 ,(0,1,2) } 10 Models for XYZ Mesons _ Q Q Quarkonium Hybrids _ g ● small_ wave function for QQ at the origin QQ in color-octet state ⟹ repulsive potential ● suppression of decays into S-wave + S-wave mesons S-wave + P-wave preferred (if kinematically accessible) Close & Page 1995, Kou and Pene 2005 ● constituent gluon picture ● Born-Oppenheimer picture 11 Models for XYZ Mesons _ Quarkonium Hybrids Q Q ● constituent gluon picture +– gluon with quantum numbers 1 spin-symmetry_ multiplets g – – –+ S-wave QQ_: {1 ,(0,1,2) } ++ +– ++ +– ++ +– P-wave QQ: {0 ,1 }, {1 ,(0,1,2) }, {2 ,(1,2,3) } ● Born-Oppenheimer picture_ – gluon field generated by QQ sources: Πu, Σu , ... spin-symmetry_ multiplets – – –+ ++ +– P-wave QQ_ in Πu field: {1 ,(0,1,2) }, {1 ,(0,1,2) } Σ – ++ +– S-wave QQ in u field: {0 ,1 } _ Q Q 12 Models for XYZ Mesons Charmonium Hybrid Y(4260) Babar 2005 - - ● 1 + - ● produced very weakly in e e_ annihilation ⟹ small wavefunction for cc at the origin ● not observed in S-wave + S-wave charm mesons 2 40 104 103 30 102 10 identify as 1 charmonium hybrid 20 3.6 3.8 4 4.2 4.4 4.6 4.8 5 Events / 20 MeV/c Close and Page 2005 10 0 3.8 4 4.2 4.4 4.6 4.8 5 13 m(+-J/) (GeV/c2) Models for XYZ Mesons _ Q q Compact Tetraquark _ ● spacially overlapping orbitals q Q ● 2-body potentials only ⟹ fall-apart decays into meson+meson unless mass is below all meson pair thresholds Vijande, Valcarce, Richard ● 3-body and higher potentials? 14 Models for XYZ Mesons _ _ Meson Molecule Q q q Q ● constituents must be narrow S-wave charm mesons: D, D*, Ds, Ds* P-wave charm mesons: D1, D2*, Ds0*, Ds1, Ds2* ● many XYZ mesons are near a charm-meson-pair threshold Are XYZ mesons near thresholds just by coincidence? 25 nonstrange thresholds between 3770 and 5150 MeV! Are charm mesons bound by their interactions? π exchange between charm mesons Tornqvist 1993 isospin-0 bound_ states near threshold –+ ++ D*D_: 0 ,1 ++ –+ +– ++ D*D*: 0 , 0 , 1 , 2 15 Models for XYZ Mesons Meson Molecules Universality of S-wave near-threshold resonances if a state is sufficiently close to a threshold within 10 MeV for charm mesons within 3 MeV for bottom mesons and if it has S-wave coupling to the threshold it is transformed by its interactions into a loosely bound molecule with universal properties determined by its small binding energy large mean-square separation of constituents: 2 ⟨r ⟩ = 1/(4μ Ebinding) _ r _ Q q q Q 16 Models for XYZ Mesons Definitive Meson Molecule: X(3872) X(3872) _ ● extremely close to threshold for D*0 D0 below threshold by 0.3±0.4 MeV Belle, CDF, LHCb ++ ● quantum numbers 1 LHCb _ ⟹ S-wave coupling to D*0 D0 must be loosely bound molecule_ _ superposition of D*0 D0 and D0 D*0 rms separation of charm mesons: 5 fm (if binding energy is 0.3 MeV) 5 fm _ D*0 D0 17 Models for XYZ Mesons Meson Molecules Bottomonium tetraquarks Zb(10610), Zb(10650) both decay into Υ(nS) π and hb(nP) π _ Zb(10610) is close to B*B_ threshold Zb(10650) is close to B*B* threshold (but they are above threshold and not close enough to be universal molecules) _ Assumption that Zb(10610) is B*B_ molecule and that Zb(10650) is B*B* molecule can explain why they both decay into Υ(nS) π and hb(nP) π Bondar, Garmash, Milstein, Mizuk, & Voloshin 2011 Is there a better explanation? 18 Models for XYZ Mesons _ _ Diquark-Onium Q q Q q ● diquark Qq: color anti-triplet, spin 0 or 1 ● for q = u,d only degenerate isospin-0 and isospin-1 multiplets quantum numbers: 0++, 0++, 0++, 0++ 1+–, 1+–, 1++, 1++ 2++, 2++ ● include q = s orbital excitations? radial excitations? proliferation of predicted states! 19 Models for XYZ Mesons q _ Hadro-Quarkonium QQ _ _ ● light quarks bound to color-singlet QQ core q Dubynskiy & Voloshin 2008 ● or light meson bound to quarkonium ● motivation: many XYZ mesons observed though single hadronic transition to specific charmonium and light meson 20 Models for XYZ Mesons Born-Oppenheimer Tetraquark ● quarkonium tetraquark can be described by the Born-Oppenheimer approximation just like quarkonium hybrids except that the gluons and light quarks are in a flavor-nonsinglet state arXiv:1305.6905 _ q _ Q Q q _ ● Q and Q move adiabatically in B-O potentials defined by energies of gluons and light quarks with isospin 1 21 QCD Theory Approaches ● Lattice QCD for charmonium S Prelovsek, Lattice QCD Review of Charmonium ... Spectroscopy, Saturday 14:00 C Thomas, Excited Charmonia ... from Lattice QCD, Sunday 9:40 ● Lattice NRQCD for bottomonium ● Born-Oppenheimer approximation for charmonium and bottomonium ● QCD Sum Rules? 22 _ Lattice QCD for cc Mesons Dudek, Edwards, Mathur, Richards 2007 Hadron Spectrum Collaboration 2012 Lattice QCD ● anisotropic lattice: 243 x 128 ● lattice spacing: a = 0.12 fm ● light quark masses: mπ = 400 MeV caveat: no extrapolation to a = 0 no extrapolation to physical u,d quark masses ● determine masses of charmonium and charmonium hybrids from cross-correlators of many operators ● identified 46 states with various JPC: J up to 4, mass up to 4.6 GeV ● discriminate between charmonium and charmonium hybrids 23 Lattice QCD for charmonium Hadron Spectrum Collaboration 2012 charmonium hybrid candidates fill out 4 spin-symmetry multiplets {1++, (0,1,2)+-}, {0++, 1+-}, {2++, (1,2,3)+-} {1--, (0,1,2)-+} 1500 L 1000 DsDs MeV H c h DD M - M 500 exotic! exotic! 0 0-+ 1-- 2-+ 1-+ 0++ 1+- 1++ 2++ 3+- 0+- 2+- 24 Charmonium Hybrids ● Lattice QCD predicts one 1-- charmonium hybrid near 4300 MeV identify that state as Y(4260) Close and Page 2005 ● extrapolations to a = 0 and to physical mπ will affect masses smaller effects on mass splittings? ● take mass of Y(4260) from experiment take mass splittings from Hadron Spectrum Collaboration predict masses for rest of ground-state hybrid multiplet 0–+: 4173±21 MeV 1–+: 4195±23 MeV 2–+: 4312±24 MeV arXiv:1305.6905 need definitive Lattice QCD calculations with extrapolations to a = 0 and
Load more

Recommended publications
  • Effective Field Theories for Quarkonium
    Effective Field Theories for Quarkonium recent progress Antonio Vairo Technische Universitat¨ Munchen¨ Outline 1. Scales and EFTs for quarkonium at zero and finite temperature 2.1 Static energy at zero temperature 2.2 Charmonium radiative transitions 2.3 Bottomoniun thermal width 3. Conclusions Scales and EFTs Scales Quarkonia, i.e. heavy quark-antiquark bound states, are systems characterized by hierarchies of energy scales. These hierarchies allow systematic studies. They follow from the quark mass M being the largest scale in the system: • M ≫ p • M ≫ ΛQCD • M ≫ T ≫ other thermal scales The non-relativistic expansion • M ≫ p implies that quarkonia are non-relativistic and characterized by the hierarchy of scales typical of a non-relativistic bound state: M ≫ p ∼ 1/r ∼ Mv ≫ E ∼ Mv2 The hierarchy of non-relativistic scales makes the very difference of quarkonia with heavy-light mesons, which are just characterized by the two scales M and ΛQCD. Systematic expansions in the small heavy-quark velocity v may be implemented at the Lagrangian level by constructing suitable effective field theories (EFTs). ◦ Brambilla Pineda Soto Vairo RMP 77 (2004) 1423 Non-relativistic Effective Field Theories LONG−RANGE SHORT−RANGE Caswell Lepage PLB 167(86)437 QUARKONIUM QUARKONIUM / QED ◦ ◦ Lepage Thacker NP PS 4(88)199 QCD/QED ◦ Bodwin et al PRD 51(95)1125, ... M perturbative matching perturbative matching ◦ Pineda Soto PLB 420(98)391 µ ◦ Pineda Soto NP PS 64(98)428 ◦ Brambilla et al PRD 60(99)091502 Mv NRQCD/NRQED ◦ Brambilla et al NPB 566(00)275 ◦ Kniehl et al NPB 563(99)200 µ ◦ Luke Manohar PRD 55(97)4129 ◦ Luke Savage PRD 57(98)413 2 non−perturbative perturbative matching Mv matching ◦ Grinstein Rothstein PRD 57(98)78 ◦ Labelle PRD 58(98)093013 ◦ Griesshammer NPB 579(00)313 pNRQCD/pNRQED ◦ Luke et al PRD 61(00)074025 ◦ Hoang Stewart PRD 67(03)114020, ..
    [Show full text]
  • Quarkonium Interactions in QCD1
    CERN-TH/95-342 BI-TP 95/41 Quarkonium Interactions in QCD1 D. KHARZEEV Theory Division, CERN, CH-1211 Geneva, Switzerland and Fakult¨at f¨ur Physik, Universit¨at Bielefeld, D-33501 Bielefeld, Germany CONTENTS 1. Introduction 1.1 Preview 1.2 QCD atoms in external fields 2. Operator Product Expansion for Quarkonium Interactions 2.1 General idea 2.2 Wilson coefficients 2.3 Sum rules 2.4 Absorption cross sections 3. Scale Anomaly, Chiral Symmetry and Low-Energy Theorems 3.1 Scale anomaly and quarkonium interactions 3.2 Low energy theorem for quarkonium interactions with pions 3.3 The phase of the scattering amplitude 4. Quarkonium Interactions in Matter 4.1 Nuclear matter 4.2 Hadron gas 4.3 Deconfined matter 5. Conclusions and Outlook 1Presented at the Enrico Fermi International School of Physics on “Selected Topics in Non-Perturbative QCD”, Varenna, Italy, June 1995; to appear in the Proceedings. 1 Introduction 1.1 Preview Heavy quarkonia have proved to be extremely useful for understanding QCD. The large mass of heavy quarks allows a perturbation theory analysis of quarkonium decays [1] (see [2] for a recent review). Perturbation theory also provides a rea- sonable first approximation to the correlation functions of quarkonium currents; deviations from the predictions of perturbation theory can therefore be used to infer an information about the nature of non-perturbative effects. This program was first realized at the end of the seventies [3]; it turned out to be one of the first steps towards a quantitative understanding of the QCD vacuum. The natural next step is to use heavy quarkonia to probe the properties of excited QCD vacuum, which may be produced in relativistic heavy ion collisions; this was proposed a decade ago [4].
    [Show full text]
  • Understanding the J/Psi Production Mechanism at PHENIX Todd Kempel Iowa State University
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2010 Understanding the J/psi Production Mechanism at PHENIX Todd Kempel Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Physics Commons Recommended Citation Kempel, Todd, "Understanding the J/psi Production Mechanism at PHENIX" (2010). Graduate Theses and Dissertations. 11649. https://lib.dr.iastate.edu/etd/11649 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Understanding the J= Production Mechanism at PHENIX by Todd Kempel A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Nuclear Physics Program of Study Committee: John G. Lajoie, Major Professor Kevin L De Laplante S¨orenA. Prell J¨orgSchmalian Kirill Tuchin Iowa State University Ames, Iowa 2010 Copyright c Todd Kempel, 2010. All rights reserved. ii TABLE OF CONTENTS LIST OF TABLES . v LIST OF FIGURES . vii CHAPTER 1. Overview . 1 CHAPTER 2. Quantum Chromodynamics . 3 2.1 The Standard Model . 3 2.2 Quarks and Gluons . 5 2.3 Asymptotic Freedom and Confinement . 6 CHAPTER 3. The Proton . 8 3.1 Cross-Sections and Luminosities . 8 3.2 Deep-Inelastic Scattering . 10 3.3 Structure Functions and Bjorken Scaling . 12 3.4 Altarelli-Parisi Evolution .
    [Show full text]
  • Strange Hadrocharmonium ∗ M.B
    Physics Letters B 798 (2019) 135022 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Strange hadrocharmonium ∗ M.B. Voloshin a,b,c, a William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN 55455, USA b School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA c Institute of Theoretical and Experimental Physics, Moscow, 117218, Russia a r t i c l e i n f o a b s t r a c t Article history: It has been recently suggested that the charged charmoniumlike resonances Zc (4100) and Zc (4200) Received 23 May 2019 are two states of hadrocharmonium, related by the charm quark spin symmetry in the same way Received in revised form 12 August 2019 as the lowest charmonium states ηc and J/ψ. It is pointed out here that in this picture one might Accepted 16 September 2019 expect existence of their somewhat heavier strange counterparts, Zcs, decaying to ηc K and J/ψ K . Some Available online 11 October 2019 expected properties of such charmoniumlike strange resonances are discussed that set benchmarks for Editor: B. Grinstein their search in the decays of the strange Bs mesons. © 2019 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license 3 (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP . Numerous new resonances recently uncovered near the open down to about 4220 MeV), has been recently invoked [11]for de- charm and open bottom thresholds, the so-called XYZ states, ap- scription of the charged charmoniumlike resonances Zc(4100) and parently do not fit in the standard quark-antiquark template and Zc(4200) observed respectively in the decay channels ηcπ [12] 1 contain light constituents in addition to a heavy quark-antiquark and J/ψπ [13].
    [Show full text]
  • Effective Field Theories of Heavy-Quark Mesons
    Effective Field Theories of Heavy-Quark Mesons A thesis submitted to The University of Manchester for the degree of Doctor of Philosophy (PhD) in the faculty of Engineering and Physical Sciences Mohammad Hasan M Alhakami School of Physics and Astronomy 2014 Contents Abstract 10 Declaration 12 Copyright 13 Acknowledgements 14 1 Introduction 16 1.1 Ordinary Mesons......................... 21 1.1.1 Light Mesons....................... 22 1.1.2 Heavy-light Mesons.................... 24 1.1.3 Heavy-Quark Mesons................... 28 1.2 Exotic cc¯ Mesons......................... 31 1.2.1 Experimental and theoretical studies of the X(3872). 34 2 From QCD to Effective Theories 41 2.1 Chiral Symmetry......................... 43 2.1.1 Chiral Symmetry Breaking................ 46 2.1.2 Effective Field Theory.................. 57 2.2 Heavy Quark Spin Symmetry.................. 65 2.2.1 Motivation......................... 65 2.2.2 Heavy Quark Effective Theory.............. 69 3 Heavy Hadron Chiral Perturbation Theory 72 3.1 Self-Energies of Charm Mesons................. 78 3.2 Mass formula for non-strange charm mesons.......... 89 3.2.1 Extracting the coupling constant of even and odd charm meson transitions..................... 92 2 4 HHChPT for Charm and Bottom Mesons 98 4.1 LECs from Charm Meson Spectrum............... 99 4.2 Masses of the charm mesons within HHChPT......... 101 4.3 Linear combinations of the low energy constants........ 106 4.4 Results and Discussion...................... 108 4.5 Prediction for the Spectrum of Odd- and Even-Parity Bottom Mesons............................... 115 5 Short-range interactions between heavy mesons in frame- work of EFT 126 5.1 Uncoupled Channel........................ 127 5.2 Two-body scattering with a narrow resonance........
    [Show full text]
  • Angular Decay Coefficients of J/Psi Mesons at Forward Rapidity from P Plus P Collisions at Square Root =510 Gev
    BNL-113789-2017-JA Angular decay coefficients of J/psi mesons at forward rapidity from p plus p collisions at square root =510 GeV PHENIX Collaboration Submitted to Physical Review D April 13, 2017 Physics Department Brookhaven National Laboratory U.S. Department of Energy USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26) Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE- SC0012704 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use or the results of such use of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
    [Show full text]
  • Two-Loop Correction to the Leptonic Decay of Quarkonium
    CERN-TH/97-353 hep-ph/9712302 December 1997 Two-lo op Correction to the Leptonic Decay of Quarkonium M. Beneke and A. Signer Theory Division, CERN, CH-1211 Geneva 23 and V.A. Smirnov Nuclear Physics Institute, Moscow State University, 119889 Moscow, Russia Abstract Applying asymptotic expansions at threshold, we compute the two-lo op QCD cor- + rection to the short-distance co ecient that governs the leptonic decay ! l l of a S -wave quarkonium state and discuss its impact on the relation b etween the quarkonium non-relativistic wave function at the origin and the quarkonium decay constant in full QCD. PACS Nos.: 13.20.Gd, 12.38.Bx Quarkonium decays played an imp ortant role in establishing Quantum Chromo dynamics (QCD) as a weakly interacting theory at short distances. Calculations of heavy quarko- nium decays usually pro ceed under the assumption that the heavy quark-antiquark b ound state is non-relativistic and that the decay amplitude factorizes into the b ound state wave function at the origin and a short-distance quark-antiquark annihilation am- plitude. One can then explain the small width of the S -wave spin-triplet charmonium state J= , b ecause it can decay only through electro-magnetic annihilation or annihila- tion into at least three gluons [1]. Today's understanding of quarkonium b ound states has re ned this picture and allows us to calculate relativistic corrections systematically at the exp ense of intro ducing further non-p erturbative parameters that characterize the b ound state. Such calculations can be done most transparently in the framework of a non-relativistic e ective eld theory (NRQCD) [2,3] that implements the factoriza- tion of contributions to the (partial) decay widths from di erent length scales.
    [Show full text]
  • Heavy P-Wave Quarkonium Production Via Higgs Decays
    PHYSICAL REVIEW D 98, 036014 (2018) Heavy P-wave quarkonium production via Higgs decays † ‡ Qi-Li Liao,1,* Ya Deng,1, Yan Yu, 1, Guang-Chuan Wang,1 and Guo-Ya Xie2 1College of Mobile Telecommunications Chongqing University of Posts and Telecom, Chongqing 401520, People’s Republic of China 2Chongqing University of Posts and Telecom, Chongqing 400065, People’s Republic of China (Received 6 July 2018; published 21 August 2018) The production of the heavy quarkonium, i.e., jðcb¯Þ½ni (or jðbc¯Þ½ni), jðcc¯Þ½ni, and jðbb¯Þ½ni- ¯ 0 0 quarkonium [jðQQ Þ½ni-quarkonium for short], through Higgs H boson semiexclusive decays is evaluated within the nonrelativistic quantum chromodynamics (NRQCD) framework, where [n] stands ¯ 0 1 ¯ 0 3 for the production of the two color-singlet S-wave states, jðQQ Þ½ S01i and jðQQ Þ½ S11i, the production ¯ 0 1 ¯ 0 3 of the four color-singlet P-wave states, i.e., jðQQ Þ½ P01i, jðQQ Þ½ PJ1i (with J ¼½0; 1; 2). Moreover, according to the velocity scaling rule of the NRQCD, the production of the two color-octet components, ¯ 0 1 ¯ 0 3 jðQQ Þg½ S08i and jðQQ Þg½ S18i, are also taken into account. The “improved trace technology” to derive the simplified analytic expressions at the amplitude level is adopted, which shall be useful for dealing with these decay channels. If all higher heavy quarkonium states decay completely to the ground states, 0 ¯ 1 0 1 it should be obtained ΓðH → jðcbÞ½ S01iÞ ¼ 15.14 KeV, ΓðH → jðcc¯Þ½ S01iÞ ¼ 1.547 KeV, and 0 ¯ 1 5 4 ΓðH → jðbbÞ½ S01iÞ ¼ 1.311 KeV.
    [Show full text]
  • Thesis, We Take Σψ Directly from Experimental Data
    QUARKONIUM TRANSPORT THEORY IN ULTRA-RELATIVISTIC HEAVY-ION COLLISIONS A Dissertation by XIAOJIAN DU Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Chair of Committee, Ralf Rapp Committee Members, Siu Ah Chin Che-Ming Ko Saskia Mioduszewski Frank Sottile Head of Department, Grigory Rogachev August 2019 Major Subject: Physics Copyright 2019 Xiaojian Du ABSTRACT The study of the fundamental strong interaction is an important vehicle for advancing our understanding of nuclear physics. Quarkonia, bound states of heavy quark-antiquark pairs, are promising probes for studying the strong force, in particular its confining prop- erty which constrains quarks and gluons to hadrons. Ultrarelativistic heavy-ion collisions (URHICs) are the only experimental method that can screen the strong force by creating a hot and dense medium. The suppression of quarkonia observed in URHICs is believed to be due to the formation of a deconfined quark-gluon plasma (QGP), a medium with un- bound quarks and gluons. In order to study this phenomenon, we utilize a transport model to describe the evolution of quarkonium states in URHICs. This model calculates the sup- pression of heavy quarkonia, as well as recombination of heavy quark-antiquark pairs, in the medium. For charmonium, in particular, the recombination is essential for describing the momentum and energy dependencies of their spectra. Based on the fact that different binding energies lead to different dissociation temperatures, a “sequential regeneration” of excited and ground-state charmonia is proposed and implemented to compare to experi- mental data in nuclear collisions.
    [Show full text]
  • How to Make Sense of the XYZ Mesons from QCD
    How to Make Sense of the XYZ Mesons from QCD Eric Braaten Ohio State University arXiv:1401.7351, arXiv:1402.0438 (with C. Langmack and D. H. Smith) supported by Department of Energy How to Make Sense of the XYZ Mesons from QCD (using the Born-Oppenheimer Approximation) ● constituent models for XYZ mesons ● Born-Oppenheimer_ approximation for QQ_ hybrid mesons Juge, Kuti, Morningstsar for QQ tetraquark mesons ● hadronic transitions of XYZ mesons XYZ Mesons _ _ ● more than 2 dozen new cc and bb mesons discovered since 2003 ● seem to require additional constituents ● some of them are tetraquark mesons ● many of them are surprisingly narrow ● a major challenge to our understanding of the QCD spectrum! Models for XYZ Mesons three basic categories _ ● conventional quarkonium QQ _ ● Q Q quarkonium hybrid g _ Q q_ ● quarkonium tetraquark q Q Models for XYZ Mesons Quarkonium Tetraquarks _ Q q ● compact tetraquark _ q Q _ _ ● meson molecule Qq qQ _ _ ● diquark-onium Qq qQ q _ ● hadro-quarkonium QQ_ q q _ ● quarkonium adjoint meson QQ_ q Models for XYZ Mesons ● little connection with fundamental theory QCD constituents: degrees of freedom from QCD interactions: purely phenomenological ● some success in describing individual XYZ mesons ● no success in describing pattern of XYZ mesons Models for XYZ Mesons Approaches within QCD fundamental fields: quarks and gluons parameters: αs, quark masses ● Lattice QCD Prelovsek, Leskovec, Mohler, … ● QCD Sum Rules? ● Born-Oppenheimer approximation _ Born-Oppenheimer Approximation for Quarkonium Hybrids ● pioneered
    [Show full text]
  • Pentaquark and Tetraquark States Arxiv:1903.11976V2 [Hep-Ph]
    Pentaquark and Tetraquark states 1 2 3 4;5 6;7;8 Yan-Rui Liu, ∗ Hua-Xing Chen, ∗ Wei Chen, ∗ Xiang Liu, y Shi-Lin Zhu z 1School of Physics, Shandong University, Jinan 250100, China 2School of Physics, Beihang University, Beijing 100191, China 3School of Physics, Sun Yat-Sen University, Guangzhou 510275, China 4School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China 5Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou 730000, China 6School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China 7Collaborative Innovation Center of Quantum Matter, Beijing 100871, China 8Center of High Energy Physics, Peking University, Beijing 100871, China April 2, 2019 Abstract The past seventeen years have witnessed tremendous progress on the experimental and theo- retical explorations of the multiquark states. The hidden-charm and hidden-bottom multiquark systems were reviewed extensively in Ref. [1]. In this article, we shall update the experimental and theoretical efforts on the hidden heavy flavor multiquark systems in the past three years. Espe- cially the LHCb collaboration not only confirmed the existence of the hidden-charm pentaquarks but also provided strong evidence of the molecular picture. Besides the well-known XYZ and Pc states, we shall discuss more interesting tetraquark and pentaquark systems either with one, two, three or even four heavy quarks. Some very intriguing states include the fully heavy exotic arXiv:1903.11976v2 [hep-ph] 1 Apr 2019 tetraquark states QQQ¯Q¯ and doubly heavy tetraquark states QQq¯q¯, where Q is a heavy quark.
    [Show full text]
  • G. A. Kozlov on Leptonic Decay of a Heavy Quarkonium with a Higgs-Boson Emission
    ¨¸Ó³ ¢ —Ÿ. 2009. ’. 6, º 1(150). ‘. 37Ä40 ”ˆ‡ˆŠ ‹…Œ…’›• —‘’ˆ– ˆ ’Œƒ Ÿ„. ’…ˆŸ ON LEPTONIC DECAY OF A HEAVY QUARKONIUM WITH A HIGGS-BOSON EMISSION G. A. Kozlov Joint Institute for Nuclear Research, Dubna A leptonic (¯ll) decay of a heavy quarkÄantiquark bound state T (QQ¯ ) with a Higgs-boson H emission is investigated. The applying of the low-energy theorem to mesonÄHiggs coupling allows one to estimate the probability of the decay T (QQ¯ ) → llH¯ . Only a simple version of the Standard Model extension containing two-Higgs doublet is considered. ‚ · ¡μÉ¥ ¨¸¸²¥¤Ê¥É¸Ö ²¥¶Éμ´´Ò° (¯ll) · ¸¶ ¤ ÉÖ¦¥²μ£μ ±¢ ·±- ´É¨±¢ ·±μ¢μ£μ ¸¢Ö§ ´´μ£μ ¸μ¸Éμ- Ö´¨Ö T (QQ¯ ) ¸ Ô³¨¸¸¨¥° ¡μ§μ´ •¨££¸ H. ·¨³¥´¥´¨¥ ´¨§±μÔ´¥·£¥É¨Î¥¸±μ° É¥μ·¥³Ò ± ±μ´¸É ´É¥ ¸¢Ö§¨ ±¢ ·±μ´¨Ö ¸ ̨££¸μ¢¸±¨³ ¡μ§μ´μ³ ¶μ§¢μ²Ö¥É ¢Ò¶μ²´¨ÉÓ μÍ¥´±Ê · ¸¶ ¤ T (QQ¯ ) → llH¯ .‚ ¸É ÉÓ¥ · ¸¸³ É·¨¢ ¥É¸Ö ²¨ÏÓ ¶·μ¸É Ö ¢¥·¸¨Ö · ¸Ï¨·¥´¨Ö ‘É ´¤ ·É´μ° ³μ¤¥²¨, ¸μ¤¥·¦ Ð Ö ¤¢ÊÌ- ̨££¸μ¢¸±¨° ¤Ê¡²¥É. PACS: 11.10.St, 12.60.Fr It is well known that some extensions of the Standard Model (SM) admit the existence of new physical bound states (hadrons), composed of heavy quarks and antiquarks including the 4th generation quarks (Q4) [1]. The question of the existence of 4th generation fermions (f4) is among the most important, intriguing and not solved yet ones in the modern elementary particle physics. We know that, e. g., the heterotic string phenomenology in E6 model leads to the 4th generation of leptons (l4)andQ4 with a relatively stable massive neutrino of 4th generation (ν4) [2].
    [Show full text]