Charmed Baryons Productions and decays

Charmed Baryons Productions and decays Atsushi Hosaka RCNP, Osaka University Reimei( ), Jan.17-20, 2016 Collaborators: Noumi, Shirotori, Kim, Sadato, Yoshida, Oka, Hiyama, Nagahiro, Yasui PTEP 2014 (2014) 10, 103D01 PRD92 (2015) 9, 094021 PRD92 (2015) 11, 114029 1. Introduction 2. Structure Masses and WF 3. Production 4. Decays Studied at J-PARC Reaction rates and structure, WF Jan. 17-20, 2016 1

1. Introduction X(3872) Exotic threshold phenomena Z(10610, 10650) Pc(4380, 4450) 3.7 3.8 3.9 4 4.1 4.2 2 M max (πj/ψ) (GeV/c ) Jan. 17-20, 2016 2 2 Events / 0.02 GeV/c 70 60 50 40 30 20 10 0 Z(3900) data Fit Background PHSP MC

Multiquarks, correlations near the threshold 4.2 Z(4430) Meson molecules Diquark Tetraquark qq qqqq qq 3.8 Z(3900) X(3872)?? 3.6 3.4 3.2 3.0 2.8 creation and rearrangement of multiquarks Correlations qq hadrons qq diquarks Jan. 17-20, 2016 3 qq

Charmed baryons for the study of qq dynamics [GeV]? 5/2 + More states at J-PARC? 1/2? 3/2 + Excited states ρ λ 3/2 1/2 1hω 1/2 + 3/2 + 1/2 + 3/2 + 1/2 + Ξ C csq Ξ C Ξ C 1/2 + Ω C css Disentangle the role of qq Ground states λ ρ 1 Ξ + cc cqq cqq Feb.16 - Mar.21, 2015 HHIQCD, YITP 4

2. Structure: what do we expect to study? A heavy quark distinguish the fundamental modes λ and ρ Place to look at qq dynamics Isotope-shift: Copley-Isgur-Karl, PRD20, 768 (1979) ρ ρ qq λ λ λ ρ m Q,m Q Jan. 17-20, 2016 ρ = λ ρ λ m Q = m u,d m Q Smooth change in mq is useful 5

Negative parity states p-wave excitations - 1/2, 3/2 Quark model 3-body calculation Yoshida, Sadato, Hiyama, Oka, Hosaka arxiv:1510.01067 (2015) Model Hamiltonian H = p 1 2 + p 2 2 + p 2 3 2m q 2m q 2M Q P2 2M tot + V conf (HO) + V spin spin (Color magnetic) +... Solved by the Gaussian expansion method Jan. 17-20, 2016 6

Excitation energies p- wave states M = m M = m s 0.7 ρ mode M = m c 0.6 0.5 HQ singlet Σ(5 / 2 ) Σ(3 / 2 ) Σ(1/ 2 ) Λ(5 / 2 ) Λ(3 / 2 ) Λ(1/ 2 ) 0.3 0.4 HQ doublet 0.5 1 2 M [GeV] 5 λ mode Jan. 17-20, 2016 7

Wave functions, ρ and λ mixing Mixing of Λ(phys) = c λ Λ( 2 λ) + c ρ Λ( 2 ρ) e.g. λ-mode dominant state: How much the other mode mixes? λ mode prob Probability c 2 Strange Λ solid Σ dashed ρ mode prob Charm Λ c * is almost pure λ mode Reflect more qq nature SU(3) M Q [GeV] Heavy quark Jan. 17-20, 2016 8

3. Productions π + N à D * + Λ c i O f Jan. 17-20, 2016 9

3. Productions π + N à D * + Λ c A. B. Kaidalov and P. E. Volkovitsky, B. Z. Phys. C 63, 517 (1994) Reaction dynamics Regge model i O f How much is charm produced? Jan. 17-20, 2016 10

3. Productions π + N à D * + Λ c A. B. Kaidalov and P. E. Volkovitsky, B. Z. Phys. C 63, 517 (1994) Reaction dynamics Regge model i O f How much is charm produced? PTEP 2014 (2014) 10, 103D01, PRD92 (2015) 9, 094021 How are they related to internal structure? Jan. 17-20, 2016 11

dσ [µb / sr] dω π p ΛK *0 π p ΣK *0 p π, Lab = 4.5 GeV 10 D.J. Krennel et al PRD6, 1220 (1972) 1 0.1 2015, Dec 09-11 1.0 0 +1.0 1.0 0 +1.0 cosθ cosθ 12

Regge model description Kim Hosaka Kim Noumi, arxiv:1509.03567 π + N K *0 + Λ of threshold whereas its effect becomes much smaller as s increases. This can od from the behavior of the u-channel Regge amplitude: T Σ s 0.79. Note that of Σ reggeon exchange is significantly different from that of Σ exchange in the rangian method, where the u-channel makes a negligibly small contribution (see mparison). σ [µb] 10 2 10 1 10 0 K R K * R N Σ R total 1 2 4 8 10-1 10-2 How much is charm produced? π p -> K *0 Λ s/s th [Regge] P lab = 3.95 GeV/c 0 1 2 3 10-4 t GeV 2 Vector-Reggeon dominance with some pseudoscalar Energy dependence is also well produced lor online). Each contribution to the total cross sections for the π p K 0 Λ reaction nction of s/s th, based on a Regge approach. The dotted and dashed curves show the s of K reggeon exchange and K reggeon exchange, respectively. The dot-dashed one ect of the nucleon in the s-channel, whereas the dot-dot-dashed one depicts that of Σ ange in the u channel. The solid curve represents the total result. The experimental en from Ref. [24] (triangles) and from Ref. [25] (circles). Jan. 17-20, 2016 13 10 2 10 0 10-2 dσ/dt [µb/gev 2 ]

Prediction to the charm production 10 2 π p -> ( K *0 Λ & D *- Λ c + ) [Regge] σ [µb] 10 0 10-2 10-4 10-4 K *0 Λ D *- Λ c + 10-6 1 2 4 8 s/s th Jan. 17-20, 2016 14

How are they related to internal structure? PTEP 2014 (2014) 10, 103D01 N i O f Various YC Quark model wave functions Jan. 17-20, 2016 15

Dynamical part ~ radial integral q(p i ) c(p f ) q eff : the momentum transfer ~ Large GS d Excited states B c (S-wave) e! σ! e i! q eff!x N(S-wave) radial ~ 1 exp q 2 eff 4A 2 B c (P-wave)! e! σ e i! q eff!x N(S-wave) radial ~ q eff A 1 exp q 2 eff 4A 2 B c (D-wave)! e! σ e i! q eff!x N(S-wave) radial ~ 2015, Dec 09-11 Transitions to excited states are not suppressed q eff A 2 exp q 2 eff 4A 2 16

Results Charm k π CM = 2.71 [GeV], k π Lab = 16 [GeV] 1.00 0.02 0.16 0.90 1.70 0.02 0.03 0.04 0.19 0.18 0.50 0.88 0.02 0.02 0.01 0.03 0.07 0.07 Feb.16 - Mar.21, 2015 HHIQCD, YITP 17 Strange k π CM = 1.59 [GeV], k π Lab = 5.8 [GeV] 1.00 0.067 0.44 0.11 0.23 0.007 0.01 0.01 0.07 0.067 0.13 0.20 0.007 0.01 0.004 0.02 0.038 0.04

Charm production spectrum Ground state Excited states l = 0 l = 1 1/ 2 + 1/ 2 3 / 2 HQ doublet J = j l + s H = j l ±1/ 2 l = 2 3 / 2 + 5 / 2 + 1 : 2 2 : 3 Jan. 17-20, 2016 18

Similarity Establishing single particle orbits: 89 Y f1/2, 3/2 d1/2, 3/2 p1/2, 3/2 s1/2 H.#Hotch#et#al.,## Phys.#Rev.#C64,#044302(2001)# Jan. 17-20, 2016 19

π + p D * + B c* (J P ) s p d π + + 89 Y K + + 89 ΛY(J P ) d Jan. 17-20, 2016 20

π + p D * + B c* (J P ) p s d π + + 89 Y K + + 89 ΛY(J P ) s p d Jan. 17-20, 2016 21

4. Decays Pion emission N π Y c * M c Y c * Y c Jan. 17-20, 2016 22

4. Decays Pion emission... On going, Nagahiro, Yasui,,, Unique feature ~ very near the threshold Λc(2625, 3/2 ) l = 1 Λ (2595, 1/2 ) c p = 102MeV p ~ 0 MeV Σc(2455, 1/2+) Ground states l=0 p = 94MeV Λc(2286, 1/2+) Place to look at the two independent operators π!!!!!! σ q!! σ p, σ p i f p p f i * Λc Σc µ q γ q φ, q γ γ 5 q µ φπ 5 π Jan. 17-20, 2016 Reimei WS@J- PARC 23

Example { ( )( ) } ( ) ( ) Λ c(1/2, λ-mode) + Σ gs c (1/2 + ) ++ π { λ ( ) (1 ) it σ = ig ω π 2 2M Λ 2MΣ m 3 2 q qλ λ + q ρ e q 2 λ 4a 2 λ e q 2 ρ 4a 2 ρ 2aλ ( ) ( ) it q σ = ig q M 2 2M Λ 2MΣ m 2m + M ω q π 2m ( 1) λ e q 2 λ 4a 2 λ e q 2 ρ 4a 2 ρ 3 2aλ Form factor a: Wave function parameter q: Pion momentum π Jan. 17-20, 2016 24

Ground (1/2, 3/2 + ) > Ground (1/2 + ) B i J P Γ full exp(γ i ) q Γ th (Σ c (J + ) ++ Λ gs c (1/2 + ;2286) + π + ) (MeV) (MeV) (MeV) (MeV) Σ c (2455) 1/2 + 2.26 (2.26) 89 4.27 4.33 (2453.98) (2.26) (ω π =0limit) Σ c (2520) 3/2 + 14.9 (14.9) 176 30.0 31.2 (2517.9) (ω π =0limit) 1/2 > Ground (1/2 + ) Preliminary results g A q = 1 g A N = 5/3 Γ th (Λ c(j ) + Σ gs c (2455; 1/2 + ) ++ π ) B i J P Γ full exp q λ-mode ρ-mode (MeV) (Γ i ) (MeV/c) doublet singlet doublet doublet (MeV) 1/2 3/2 1/2 1/2 3/2 3/2 5/2 Λ c (2595) 1/2 2.6 π 0.15-0.29 0 0.65 1.20 (2592.25) (0.624) π 0 1.23 2.36 5.29 9.69 total 1.38 2.66 5.94 10.89 Λ c (2625) (3/2 ) < 0.97 101 5.4 0.024 0 24.0 0.013 0.023 0.010 (2628.11) (0.0485) 10.7 0.039 45.1 0.019 0.034 0.015 Jan. 17-20, 2016 x 3 x 3 Λ c (2765)?? 50 263 20.4 46.7 2.6 3.9 0 107.8 224.0 1.4 1.9 2.5 3.4 1.1 1.5 (2766.6) (not seen)

Decays right on the threshold Λ c 2595; 1/2 + Σ c 2455 ++ π : π π + π Finite Γ Σc Λ c Λ c Σ c gs++ 140 2595 2455 Σ c gs++ π + Finite Γ Σc Λ c gs+ Λ c gs+ Γ = 2.6 MeV 24 % = 0. (isospin sym. assumed [P = 2. 26 MeV = 2. 26 MeV M Λ(2595) < M Σ 2455 ++ + m π Γ π = 0? Oct. 5-10, 2015 Partial decay width Γ i [MeV] (~transition cross section) 8 Partial decay width Γ i [MeV] (~transition cross section) 6 4 2 0 8 6 4 2 0 2.58 M Σ 2455 + + m π 0 2.585 Γ π 0 2.59 s [GeV] NUFRA2015 2.595 2.595 H. Nagahiro Γ π 0 > Γ π ~ phase space Γ π 2.6 2.605 Λ c Λ c 2625 3/2 2595 1/2 ~ 138 MeV 26

Summary Heavy quarks identify and disentangle different modes of baryons, ρ and λ modes Productions are useful for structure study A similar feature with hyper nuclei Charm baryons could be abundantly produced Decays are useful to further understand the structure Jan. 17-20, 2016 27

1. Introduction Hyper nuclei Λ Go into deep inside Established shell structure Charmed baryons ρ λ Q Causes isotope- shift Will discriminates modes Three particles Internal ρ and λ modes Jan. 17-20, 2016 28

Another interest: Exotics - Multiquarks Jan. 17-20, 2016 29

LHCb found Pentaquarks = cc bar uud http://arxiv.org/abs/1507.03414 7-8 TeV pp collision > Λ b Λ b J /ψ, p!" # $#, K ] 2 [GeV ψp J/ m 2 26 24 22 LHCb 20 18 16 2 3 4 5 6 2 mkp 2 [GeV ] Jan. 17-20, 2016 30

2. Structure: what do we expect to study? A heavy quark distinguish the fundamental modes λ and ρ Place to look at qq dynamics Isotope-shift: Copley-Isgur-Karl, PRD20, 768 (1979) ρ λ ρ = λ Jan. 17-20, 2016 31

4. Decays N π Y c * M c Y c * Y c Jan. 17-20, 2016 32

ρ-modes Decays of baryons π J P J P + π(0,l π ) Jan. 17-20, 2016 33

ρ-modes Decays of baryons = of diquarks j P j P + π(0,l π ) π J P J P + π(0,l π ) Two conditions must be satisfied for baryons and for diquarks Λ c (1/ 2,ρ) Σ c (1/ 2 +,GS) + π d( 3 P 0 ) d( 3 S 1 ) + π is not allowed Jan. 17-20, 2016 34

Model Hamiltonian H = p 2 1 + p 2 2 + p 2 3 2m q 2m q 2M Q P2 2M tot + V conf (HO) + V spin spin (Color magnetic) +... Solved by the Gaussian expansion method Jan. 17-20, 2016 35

ωω ρλ = ω λ ρ 1 3 1+ 2m M 1/2 = 1 ( 1+ 2x ) 3 1/2 cqq bqq ccq qqq bbq &2012 JPARC<Collab M/m Jan. 17-20, 2016 36

Strategy: Forward peak (high energy) à t-channel dominant We look at: (1) Absolute values by (Λ c /Λ s ) by the Regge model, K*, D * Vector-Reggeon (2) Ratios of B c *(λ modes) / B c by a one step process of Qd picture for λ-mode Pion-induced reaction π + p à D * + B c * π D * Jan. 17-20, 2016 37 p d D * Reggeon Quark model WF B c *

Unique feature ~ very near the threshold Λ c *(2625, 3/2 ) Λ c *(2595, 1/2 ) ~ 140 MeV Σ c (2455, 1/2 + ) Place to look at the two independent operators Λ c * 4. Decays Pion emission! p i! σ! q On going, Nagahiro and Yasui π! p f Σ c p = 102MeV; allowed p ~ 0; marginally allowed p = 94MeV; allowed Λ c (2286, 1/2 + )! σ! p i,! σ! p f qγ 5 qφ π, qγ µ γ 5 q µ φ π Jan. 17-20, 2016 38

Actual computations Λ c * (P-wave excitations, J P ) Σ c (2455, 1/2 + ) + π π Quark model (H.O.) wave functions λ ρ Sd = 0, 1 l λ,ρ = 1 S Q = 1/2 } J Light = 0,1,2 JTotal }= 1/2, 3/2, 5/2 } } HQ doublet HQ singlet m = 0.4 GeV, k = 0.03 GeV 3 M = 1.5 GeV R2 1/2 = 0.5 fm g A (q) = 1, f π = 93 MeV L πqq = g A (q) Jan. 17-20, 2016 39 f π qγ µ γ 5 q µ φ π

Initial baryons Λc * Λc(2595) 2592.25 Λc(2625) 2628.11 Λc(2765) Σc?, 2766.6 Λc(2880) 2881.63 Λc(2940) 2939.3 Γexp (full ) [MeV] p [MeV] Γcalc(Λc * > Σc(2455) π) [MeV] λ-mode, lλ=1 ( ρ-mode, lρ=1 Doublet d( 1 S0) [lλ, c] 1/2, Singlet [d( 3 P0)] 1/2 Doublet [d( 3 P1) c] 1/2, 3/2 Doublet [d( 3 P2) c] 3/2, 5/2 1/2 3/2 1/2 1/2 3/2 3/2 5/2 2.6 1.7* * * * * * * < 0.97 (102) 50 (262 ) 5.8 (376) 17 (427) 18 0.1 0** 81 0.04 0.08 0.03 76 8 0** 390 4.5 7.8 3.6 107 37 0** 624 21 37.5 17 110 66 0** 700 38 64 29 * Almost threshold carefully studied, ** Forbidden (selection rule) 1/2 : s- wave πσ decay 3/2, 5/2 + : d, f- wave πσ decay > suppressed by power (q/a) 4, 6 Λ c (2880) and Λ c (2940) could be higher spin states? Jan. 17-20, 2016 40