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The Future of Heavy Flavor and Exotic Hadron Production in RHIC and LHC

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The Future of Heavy Flavor and Exotic Hadron Production in RHIC and LHC The Future of Heavy Flavor and Exotic Hadron Production in RHIC and LHC Xiaojun Yao MIT Snowmass Energy Frontier Preparatory Joint Topical Group Sessions July 8, 2020 Quarkonium Production: Factorization J/ψ Factorization in proton proton collision c c¯ p+p H+X i+j (QQ¯) +X σ ! = f f σ ! n i ⌦ j ⌦ hOni proton PDF short-distance production long-distance matrix element: of heavy quark pair evolution of pair into quarkonium universal QGP effects: dissociation, Heavy ion nuclear PDF (re)combination, energy loss etc In heavy ion, try to understand modifications from nuclear mediums Test universality of LDME in high multi p-p X.Dong July 1 9:50 am !2 Recent Theoretical Insights from Open System In vacuum, quarkonium described by Schrödinger equation @ 2 i (r)= r + V (r) (r) @t − M h i 1.0 Start with 1S, closed system 1S probability is conserved 0.8 0.6 1S wavefunction (t = 0) = 1S | i | i 0.4 1S (t) 2 =1 |h | i| 0.2 0.0 0.0 0.5 1.0 1.5 2.0 r !3 Recent Theoretical Insights from Open System In QGP, quarkonium described by stochastic Schrödinger equation @ 2 i (r)= r + V (r) (r) + iγ(r)+⇠(r, t) (r) @t − M − h i h i 1.0 Start with 1S, open system 1S probability NOT conserved 0.8 Stochastic forces —> wavefunction decoherence (t = 0) = 1S 0.6 | i | i 1S (t) 2 < 1 0.4 |h | i| 0.2 Dissociation of 1S 2 0.0 2S (t) > 0 if 2S exists 0.0 0.5 1.0 1.5 2.0 |h | i| r Recombination of 2S ! Correlated/uncorrelated recombination: from correlated pair from same/differential initial hard vertices !4 Upsilon in 5020 GeV PbPb Collision with cross-talk (correlated) recombination without cross-talk recombination 1S theory 2S syst 1S w/o cross recombination 1.0 1S syst 2S stat 1.0 1S syst 1S stat 3S theory 1S stat 2S theory 3S 95% CL 0.8 2S w/o cross recombination 0.8 2S syst 2S stat 0.6 0.6 3S w/o cross recombination AA AA 3S 95% CL R R 0.4 0.4 0.2 0.2 0.0 0.0 0 100 200 300 400 0 100 200 300 400 Npart Npart Nuclear PDF needs better constrained CMS arXiv:1805.09215 X.Yao, W.Ke, Y.Xu, S.A.Bass, B.Müller, arXiv:2004.06746 !5 Experimental Evidence of Correlated Recombination with cross-talk (correlated) recombination without cross-talk recombination 2S 2S w/o cross recombination 1.0 1P 1P w/o cross recombination 0.8 0.4 0.6 AA AA R R 0.4 0.2 0.2 0.0 0.0 0 100 200 300 400 0 100 200 300 400 Npart Npart Dissociation rate of 1P ~ dissociation rate of 2S, due to similar binding energy/size In medium, P(1P—>2S) ~ P(2S—>1P), via dissociation and correlated recombination But more 1P states produced initially than 2S, so more 2S regenerated than 1P !6 Experimental Evidence of Correlated Recombination 1.0 w/ cross recombination 0.8 ) ) S P (2 (1 0.6 AA AA R R 0.4 0.2 0 5 10 15 20 pT (GeV) Importance of correlated recombination can be checked at RHIC and LHC For RHIC, need to distinguish between 2S and 3S, sPHENIX J. Huang, July 1 10:05 am !7 X(3872): Structure PC ++ J =1 mX = mD0 + mD¯ 0 0.3 MeV ⇤ ± ccq¯ q¯ D D* tetraquark molecule Br[D0D¯ 0⇡0] > 0.4 Anything that can mix in quantum mechanics will mix 0 ¯ 0 Br[D D⇤ ] > 0.3 Must have large overlap with molecule wavefunction Br[J/ + ] > 0.055 ··· !8 X(3872): Production Any calculation needs to explain these simultaneously mX = mD0 + m ¯ 0 0.3 MeV D⇤ ± Hard to be produced in QGP phase Interactions during the hadronic gas phase: dissociation v.s. (re)combination Determining its structure needs interplay between theory and experiment Interesting to measure it in p-A collisions, also at low pT in A-A collisions !9 Doubly Charmed Baryon ++ • LHCb observed a new baryon ⌅ cc (ccu): u bound around cc core LHCb, Phys. Rev. Lett. 119, no.11,112001 (2017) • Pair of heavy Q in anti-triplet forms bound state (diquark) QQ anti-triplet c Q Q ¯ singlet c color neutral colored c¯ exist in vacuum not exist in vacuum c exist in QGP J/ cc diquark (1S) • Heavy diquark in QGP: dissociation, recombination (similar to quarkonium), carry color, energy loss different from quarkonium • Hadronize into doubly charmed baryon • Can help to test recombination as production mechanism !10 Doubly Charmed Baryon Production in Heavy Ion Collisions ++ XY, B.Mueller, Phys.Rev.D97 Predicted production rate of ⌅cc 0.5 (2018) no.7, 074003 in 2760 GeV PbPb, -1<y<1, 0<pT<5 GeV, 0.02 per collision 0.4 ++ cc 2 T 0.3 ⌅ p d N With melting temperature = 250 MeV: d 0.0125 per collision 0.2 0.1 Compare: c quark rate ~10 per collision 0.0 0 1 2 3 4 5 pT (GeV) Production rate from initial hard collision probably small Study recombination from measurements !11 Doubly Heavy Tetraquark Production in Heavy Ion Same calculation can be extended to study doubly heavy tetraquark (bound state) Only difference: at hadronization coalescence with two light quarks v.s. one Heavy quark diquark symmetry Hadronization of doubly heavy baryon similar to hadronization of singly heavy meson Hadronization of doubly heavy tetraquark similar to hadronization of singly heavy baryon Enhancement of singly heavy baryon Expect enhancement of observed in heavy ion/high multi p-p doubly heavy tetraquark G. M. Innocenti July 1 9:05 am Heavy ion collision may be a good place to search for doubly heavy tetraquarks !12 Summary • Quarkonium production: • Test universality of LDME and factorization in high multi p-p collisions • Correlated recombination motivated from open quantum system; experimental signal: Raa(1P)/Raa(2S) for bottomonium • Exotic hadrons: • X(3872): more measurements help understand its structure • Doubly heavy baryon/tetraquark, (re)combination, heavy quark diquark symmetry, enhanced production—>search for these tetraquarks in heavy ion • Fragmentation in heavy-flavor jets: universal in ee, pp, pA? Lambda_c v.s D !13 Coupled Transport Equations of Heavy Flavors open heavy quark antiquark @ + ( + x˙ + x˙ ¯ )f ¯ (x , p , x ¯ , p ¯ ,t)= ¯ + − @t Q · rxQ Q · rxQ¯ QQ Q Q Q Q CQQ − CQQ¯ CQQ¯ each quarkonium state @ + ( + x˙ x)fnls(x, p,t)= − nl = 1S, 2S,1P etc. @t · r Cnls − Cnls b B¯ b hadronization b 1S 1S diffuse b ¯ ¯b propagate b ¯b hadronization ¯b B initial QGP medium expands and cools hadron gas production time !14 Coupled Transport Equations of Heavy Flavors open heavy quark antiquark @ + ( + x˙ + x˙ ¯ )f ¯ (x , p , x ¯ , p ¯ ,t)= ¯ + − @t Q · rxQ Q · rxQ¯ QQ Q Q Q Q CQQ − CQQ¯ CQQ¯ each quarkonium state @ + ( + x˙ x)fnls(x, p,t)= − nl = 1S, 2S,1P etc. @t · r Cnls − Cnls recombine if b T < melting T b b 1S 1S nL nL b ¯ ¯ b ¯b b 1S,2S,1P… ¯b ¯b nL nL b b from other open b initial QGP medium expands and cools hadron gas production time !15 Coupled Transport Equations of Heavy Flavors open heavy quark antiquark @ + ( + x˙ + x˙ ¯ )f ¯ (x , p , x ¯ , p ¯ ,t)= ¯ + − @t Q · rxQ Q · rxQ¯ QQ Q Q Q Q CQQ − CQQ¯ CQQ¯ each quarkonium state @ + ( + x˙ x)fnls(x, p,t)= − nl = 1S, 2S,1P etc. @t · r Cnls − Cnls b correlated recombination b b 1S 1S nL nL b ¯ ¯ b ¯b b 1S,2S,1P… ¯b ¯b nL nL b b from other open b uncorrelated recombination !16.
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