Exo$c hadrons with heavy quarks

Transcription

1 Exo$c hadrons with heavy quarks Molecules Hadrons from hadrons Atsushi Hosaka Research Center for Nuclear Physics (RCNP) Osaka University Hirschegg, Hadrons from quarks and gluons Contents 1. Introduc$on HQ symmetry and chiral symmetry 2. Hadronic molecules with heavy quarks DN and Z b 's January 2014 Hadrons@Hirschegg 1

2 1. Introduc$on Hadron Physics Evidence of Higgs (like) has been observed Low energy QCD for Hadrons is perhaps least understood Lagrangian is simple but not easy to solve Long history: Experiments, Models (Empirical rules), Computer simula$ons (LaWce QCD, Kei Breakthrough to a new understanding January 2014 Hadrons@Hirschegg 2

3 1. Introduc$on Hadron Physics Evidence of Higgs (like) has been observed Low energy QCD for Hadrons is perhaps least understood Lagrangian is simple but not easy to solve Long history: Experiments, Models (Empirical rules), Computer simula$ons (LaWce QCD, Kei Yet, recent (last decade) observa$ons have revealed unexpectedly rich spectrum near thresholds at KEK, Spring- 8, J- PARCBES, RHIC, LHC, Breakthrough to a new understanding January 2014 Hadrons@Hirschegg 3

4 Hadrons are composite Many resonant states Par$cle data book (PDG) January

5 But all of them seem to have minimum numbers (2 or 3) of valence quarks Mesons ~ qq q q Baryons ~ qqq q q q Then ques$on: why not states such as Gluon excita$ons (glueballs, hybrids, ) Mul$quarks, tetra, penta, Mul$- hadron hadrons (hadronic molecules) Recently observed rich spectrum with the Heavy quarks January 2014 Hadrons@Hirschegg 5

6 Data from KEK, Talk by Bondar X(3872) Zc(3900) State Mass (MeV) Width (MeV) Decay Production Ys(2175) 2175±8 58±26 ff 0 ISR Manifestly, implicitly non- qq mesons X(3872) ±0.33 <0.95 J/ypp, J/yg B decay X(3872) / /-1.8 D *0 D 0 B decay Z(3940) 3929±5 29±10 DD gg X(3940) 3942±9 37±17 DD* Double-charm Y(3940) 3942±17 87±34 J/yw B decay Y(4008) / /-80 J/ypp ISR Z(4051) / /-28 pc c1 B decay X(4160) 4156± /-65 D*D* Double-charm Z(4248) / /-72 pc c1 B decay Y(4260) 4264±12 83±22 J/ypp ISR Y(4350) 4361±13 74±18 y pp ISR Z(4430) ± /-18 y p B decay Y(4660) 4664±12 48±15 y pp ISR Y b (10890) ± /-7.6 ppυ(ns) e + e - annihilation Y(3915) 3915±4 17±10 J/yw gg X(4350) / /-14 J/yf gg h b (1P) ±1.5 MM(pp) Υ(5S) /Y b decay Zb(10610) Zb(10650) h b (2P) /-1.2 MM(pp) Υ(5S) /Y b decay Z b (10610) ± ±2.5 (Υ(nS) or h b ) p Υ(5S) /Y b decay Z b (10650) ± ±3.2 (Υ(nS) or h b ) p Υ(5S) /Y b decay January 2014 Hadrons@Hirschegg 6

7 Two features Heavy par$cles are easy to be bound Kine$c energy is suppressed If there is an acrac$ve interac$on Pion exchange between light quarks open heavy flavors = Requirement of chiral symmetry Q q OPEP q Q January 2014 Hadrons@Hirschegg 7

8 Charmonium Open charm threshold X(3872) D*D* DD* DD January

9 Charmonium Q q q Q Q Q X(3872) D*D* DD* DD January 2014 Hadrons@Hirschegg 9

10 We expect clusterized mul$quarks Near threshold π, ρ, ω ccqq D D Multiquarks rearrange into heavy hadrons è Heavy hadrons interacting by an attractive force OPEP ß Chiral symmetry January 2014 Hadrons@Hirschegg 10

11 Analogous to 12C 02+ Hoyle state 7.6 MeV M. Itoh et al, PRC84,054308(2011) "Physics Viewpoint" (RCNP experiment) January

12 2. Hadronic molecules with heavy quarks (1) DN and BN cqqqq bqqqq (2) Z b and related states January 2014 Hadrons@Hirschegg 12

13 (1) DN and BN Yamaguchi, Yamaguchi, Yasui and Hosaka Phys.Rev.D84: (2011), D85, (2012) Ohkoda, Yamaguchi, Yasui and Hosaka Phys.Rev. D86: , , (2012) January

14 SD mixing by the tensor force Yasui-Sudoh, PRD80, , 2009 Yamaguchi-Ohkoda-Yasui and Hosaka, PRD84:014032,2011 Heavy Q symmetry D ~ D * Spin- dependent force suppressed m K * m K ~ 400 MeV m D * m D ~ 140 MeV m B * m B ~ 45 MeV 1 2 Coupled channels of DN(S), D * N(S), D * N(D) D D * N N N Tensor of OPEP January 2014 Hadrons@Hirschegg 14 0 l = π 1 l = π D

15 Bound and resonant states Phys.Rev.D85, (2012) DN BN E B 2.14 MeV 23.0 MeV size 3.2 fm 1.2 fm January 2014 Hadrons@Hirschegg 15

16 e (2) Z b (10610, 10650) and related states b b (5S) arxiv: v1 [hep- ex]; PRL 108, (2012) ~11 GeV Talk by Bondar e - π π Z b1 Z b2 Invariant mass analysis 10653, (3S, 10355) (2S, 10023) (1S, 9460) I G (J P ) = 1 + (1 + ) h b(2p, 10259) h b(1p, 9898) Three-body decay January 2014 Hadrons@Hirschegg 16

17 Invariant mass of πυ(ns) πυ(1s) πυ(2s) πυ(3s) In all cases, twin peaks are observed January

18 Characters States appear near the thresholds Masses of Z b (10610), Z b (10650) are similar Heavy spin changing processes occur à Z b à π h b π HQ forbidden process occurs equally with allowed ones Explained by BB* molecules January 2014 Hadrons@Hirschegg 18

19 Z b 's as B (*) B (*) molecules Bondar et al, Phys.Rev. D84 (2011) Ohkoda, Yamaguchi, Yasui, Sudoh and Hodaka, Phys.Rev. D86 (2012) Masses 2. Transi$ons: Heavy quark selec$on rules 3. Decays into bocomonium q Q π ρ ω q Q Coupled channels of BB, BB*, B*B* in a π, ρ, ω poten$al model January 2014 Hadrons@Hirschegg 19

20 1. Masses, π, ρ, ω poten$al model Similar to the model for the DN Ohkoda, Yamaguchi, Yasui, Sudoh and Hodaka, Phys.Rev. D86 (2012) January

21 Transi$ons: Heavy quark selec$on rules M. B. Voloshin, Phys. Rev. D 84, (2011) Ohkoda, Yamaguchi, Yasui, Hosaka, Phys.Rev. D86 (2012) [MeV] (5S) η(3s) η(2s) (3S) (2S) Produc$on h b (2P) h b (1P) Decays B (*) B (*) molecules χ b0 (2P) χ b1 (2P) χ b2 (2P) χ b0 (1P) χ b1 (1P) χ b2 (1P) (1 3 D 2 ) B*B* B*B BB 9500 η(1s) (1S) J PC January 2014 Hadrons@Hirschegg 21

22 HQ selec$on rules J tot = J H + j l Separately conserved Heavy-light B (*) B (*) Recoupling: [[J H1 j l1 ][J H2 j l2 ]] J tot à [[J H1 J H2 ][j l1 j l2 ]] J tot January 2014 Hadrons@Hirschegg 22

23 HQ selec$on rules J tot = J H + j l Separately conserved Heavy-light B (*) B (*) Recoupling: [[J H1 j l1 ][J H2 j l2 ]] J tot à [[J H1 J H2 ][j l1 j l2 ]] J tot Z b (10650) B B ( 3 S 1 ) : [ [b q] 1, [ bq] 1] 1 = 1/2 1/2 1 [ ˆ1ˆ1Ĥˆl 1/2 1/2 1 [b b] H, [ qq] l] 1 H,l H l 1 = 1 (0 H 2 1 l )+ 1 (1 H 2 0 l ) Z b (10610) 1 2 (B B B B)( 3 S 1 ): 1 (0 H 2 1 l ) 1 (1 H 2 0 l ) January 2014 Hadrons@Hirschegg 23

24 Example: Z b 0 à χ bj γ Heavy-light recoupling M1 M1 E2 M1 E2 January 2014 χ b0 γ (1 + ) χ b0 γ (1 H 1 l ) J=0 (0 H 1 l ) = 1 χ b1 γ(0 + ) 3 (1 H 0 l ) 1 5 (1 H 1 l ) J=1 + (1 H 1 l ) J=1 3 3 (1 H 2 l ) J=1 χ b1 γ(1 + ) 1 (1 H 0 l ) (1 H 1 l ) J= (1 H 2 l ) J=1 χ b1 γ(2 + ) (1 H 1 l ) J=1 + 5 χ b2 γ(1 + ) 3 (1 H 0 l )+ χ b1 γ (1 + ) χ b1 γ (2 + ) χ b2 γ (1 + ) χ b2 γ (2 + ) χ b2 γ(2 + ) Only M1 allowed E2 forbidden 2 (1 H 2 l ) J= (1 H 1 l ) J= (1 H 2 l ) J=1 3 2 (1 H 1 l ) J= (1 H 2 l ) J=2 Γ(Z 0 b χ b0γ) : Γ(Z 0 b χ b1γ) : Γ(Z 0 b χ b2γ) 1 Hadrons@Hirschegg : 3 : 5 24

25 Produc$on f(w b0 π) : f(w b1 π) : f(w b1 π) : f(w b2 π) : f(w b2 π) 2 : 9 : 4.5 : 9 : 12 [MeV] (5S) η(3s) (3S) h b (2P) χ b0 (2P) χ b1 (2P) χ b2 (2P) (1 3 D 2 ) B*B* B*B BB η(2s) (2S) h b (1P) χ b0 (1P) χ b1 (1P) χ b2 (1P) 9500 η(1s) (1S) Only W b1 can decay into η b and h b J PC Γ(W b0 Υπ) : Γ(W b1 Υπ) : Γ(W b1 Υπ) : Γ(W b2 Υπ) : Γ(W b2 Υπ) ( 4 : 1 : 1 : 3 : 1 January 2014 Hadrons@Hirschegg 25

26 3 Decays Z b (10610, 10650) à Υ(nS) + π Z b Υ(nS) Z b π π BB* Υ(3S) Υ(2S) Υ(1S) Theory Theory 1/13-1/17 Hadrons@Hirschegg 26

27 3 Decays Z b (10610, 10650) à Υ(nS) + π Z b Υ(nS) Z b π π BB* è B (*) B (*) Υ(3S) Υ(2S) Υ(1S) Theory Theory 1/13-1/17 Hadrons@Hirschegg 27

28 Summary In the heavy quark region many interes$ng states are observed Many candidates for hadronic molecules Chiral symmetry with the pion and heavy quark symmetry Exco$c pentaquark baryons are predicted Z b 's are good candidates of hadronic molecules Decays of Z b should be tested by experiment (SuperBelle) January 2014 Hadrons@Hirschegg 28

29 Loosely bound states: I, J P = 0, 1/2 Qq- qqq DN BN E B 2.14 MeV 23.0 MeV size 3.2 fm 1.2 fm DN Three coupled- channels BN January 2014 Hadrons@Hirschegg 29

30 Hadrons are around thresholds R=10/3 R=11/3 R=2 1 GeV 1 GeV ud s Mass c b generavon GeV in Log scale January 2014 Hadrons@Hirschegg 30

31 Data from Belle Talk by Bondar yesterday e+e- collider at 11.5 GeV (CM) January