New spectrum of negative-parity doubly charmed baryons Mao-Jun Yan - - PowerPoint PPT Presentation
New spectrum of negative-parity doubly charmed baryons Mao-Jun Yan Institute of Theoretical Physics, CAS School of Physics, BUAA Collaborators: Xiao-Hai Liu, Feng-Kun Guo, Sergi Gonzalez-Solis, C. Hanhart, U.-G. Meiner & B.S. Zou.
Mao-Jun Yan
Institute of Theoretical Physics, CAS School of Physics, BUAA Collaborators: Xiao-Hai Liu, Feng-Kun Guo, Sergi Gonzalez-Solis,
2019-08-20
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 1 / 20
1
Doubly charmed baryon in observation
2
Heavy antiquark-diquark symmetry
3
Doubly charmed baryon spectrum with JP = 1
2 − 4
Summary
5
Backup slides
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 2 / 20
First observation of Ξ+
cc in Ξ+ cc → Λ+ c K−π+
SELEX, PRL89(2002)
Confjrmation of Ξ+
cc(3520) via its decay to pD+K−
SELEX, PLB628 (2005)
Search for
cc and cc
in e e annihilations , No signal
BaBar, PRD74(2006)
Search for
cc in cc c K
, No signal
LHCb, JHEP1312(2013)
Lattice calculation:
cc
.
Observation of
cc
in
c K
mass spectrum
LHCb, PRL119(2017) Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 3 / 20
First observation of Ξ+
cc in Ξ+ cc → Λ+ c K−π+
SELEX, PRL89(2002)
Confjrmation of Ξ+
cc(3520) via its decay to pD+K−
SELEX, PLB628 (2005)
Search for Ξ+
cc and Ξ++ cc
in e+e− annihilations , No signal
BaBar, PRD74(2006)
Search for Ξ+
cc in Ξ+ cc → Λ+ c K−π+, No signal
LHCb, JHEP1312(2013)
Lattice calculation:
cc
.
Observation of
cc
in
c K
mass spectrum
LHCb, PRL119(2017) Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 3 / 20
First observation of Ξ+
cc in Ξ+ cc → Λ+ c K−π+
SELEX, PRL89(2002)
Confjrmation of Ξ+
cc(3520) via its decay to pD+K−
SELEX, PLB628 (2005)
Search for Ξ+
cc and Ξ++ cc
in e+e− annihilations , No signal
BaBar, PRD74(2006)
Search for Ξ+
cc in Ξ+ cc → Λ+ c K−π+, No signal
LHCb, JHEP1312(2013)
Lattice calculation: Ξcc(3610)(23)(22).
Observation of
cc
in
c K
mass spectrum
LHCb, PRL119(2017) Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 3 / 20
First observation of Ξ+
cc in Ξ+ cc → Λ+ c K−π+
SELEX, PRL89(2002)
Confjrmation of Ξ+
cc(3520) via its decay to pD+K−
SELEX, PLB628 (2005)
Search for Ξ+
cc and Ξ++ cc
in e+e− annihilations , No signal
BaBar, PRD74(2006)
Search for Ξ+
cc in Ξ+ cc → Λ+ c K−π+, No signal
LHCb, JHEP1312(2013)
Lattice calculation: Ξcc(3610)(23)(22).
Observation of Ξ++
cc (3621) in Λ+ c K−π+π+ mass spectrum
LHCb, PRL119(2017) Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 3 / 20
heavy quark is a static color (anti-)triplet in heavy meson. mQv ≫ ΛQCD, heavy diquark serves as a point-like color anti-triplet source,like a heavy anti-quark in heavy meson. It relates doubly-heavy baryons to anti-heavy mesons.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 4 / 20
2 −
Following heavy anti-quark-diquark symmetry, there is a bridge between charmed mesons and doubly charmed baryons.
D∗
s0(2317)
D∗
s0(2317) is understood as DK bound state mainly.
PRD76(2007) ;F.K. Guo et al PLB(641)(2006), EPJ.A40(2009), PR D87 (2013); L.S. Geng et al PRD89(2014);
Extended to doubly charmed baryon, Prediction:
cc
with mass m
cc
mDs mD GeV. While SU(3) multiplet calculated for GBs scattering ofg ground states of doubly charmed baryons.
F.-K. Guo and U.-G. Meißner PRD84(2011); Zhi-Hui Guo, PRD96 (2017)
Does inner structure of heavy diquark contribute to spectrum?
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 5 / 20
2 −
Following heavy anti-quark-diquark symmetry, there is a bridge between charmed mesons and doubly charmed baryons.
D∗
s0(2317)
D∗
s0(2317) is understood as DK bound state mainly.
PRD76(2007) ;F.K. Guo et al PLB(641)(2006), EPJ.A40(2009), PR D87 (2013); L.S. Geng et al PRD89(2014);
Extended to doubly charmed baryon, Prediction: Ωcc (1/2−) with mass mΞcc + mD∗
s0(2317) − mD ≈ 4.1GeV.
While SU(3) multiplet calculated for GBs scattering ofg ground states of doubly charmed baryons.
F.-K. Guo and U.-G. Meißner PRD84(2011); Zhi-Hui Guo, PRD96 (2017)
Does inner structure of heavy diquark contribute to spectrum?
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 5 / 20
2 −
Following heavy anti-quark-diquark symmetry, there is a bridge between charmed mesons and doubly charmed baryons.
D∗
s0(2317)
D∗
s0(2317) is understood as DK bound state mainly.
PRD76(2007) ;F.K. Guo et al PLB(641)(2006), EPJ.A40(2009), PR D87 (2013); L.S. Geng et al PRD89(2014);
Extended to doubly charmed baryon, Prediction: Ωcc (1/2−) with mass mΞcc + mD∗
s0(2317) − mD ≈ 4.1GeV.
While SU(3) multiplet calculated for GBs scattering ofg ground states of doubly charmed baryons.
F.-K. Guo and U.-G. Meißner PRD84(2011); Zhi-Hui Guo, PRD96 (2017)
Does inner structure of heavy diquark contribute to spectrum?
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 5 / 20
2 −
Size of doubly charmed baryon
rd ≈ 1/(mQvQ) ≈ 0.25 fm with mQvQ ≈ 800 MeV rq ≈ 1/ΛQCD ≈ 0.8 fm with ΛQCD ≈ 250 MeV.
rd rq ≈ 0.3
Value of mQvQ is given in J. Hu and T. Mehen
PRD73,054003(2006)
Spin structure in heavy diquark
⃗ JQQ = ⃗ SQQ + ⃗ LQQ, SQQ = 1, LQQ = 0 in ground state, P(+) SQQ = 0, LQQ = 1 in P-wave excitation. P(−)
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 6 / 20
2 −
Potential of P-wave excitation in heavy diquark: VP(cc) = 1
2VP(c¯
c) is predicted in quark model. MψP
cc − Mψcc ≈ (Mhc − MJ/ψ)/2 = 214 MeV. T.Mehen PRD96 (2017)
Something new?
should be a degree of freedom in spectrum of doubly charmed baryon. (s- and u- channel)
consideration?
P cc
couples to
cc
in S-wave
P P cc
u
cc
h c This term breaks HQSS and is expected to be
QCD mc
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 7 / 20
2 −
Potential of P-wave excitation in heavy diquark: VP(cc) = 1
2VP(c¯
c) is predicted in quark model. MψP
cc − Mψcc ≈ (Mhc − MJ/ψ)/2 = 214 MeV. T.Mehen PRD96 (2017)
Something new?
should be a degree of freedom in spectrum of doubly charmed baryon. (s- and u- channel)
consideration?
ψP
cc( 1 2 −) couples to ψccφ in S-wave
LP = λ ¯ ψP
ccγµuµψcc + h.c.
This term breaks HQSS and λ is expected to be O(ΛQCD/mc) = O(0.2) ≪ 1 T. Mehen et al PRD73,054003(2006), PRD96,094028(2017)
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 7 / 20
2 −
Vs = 2λ2 F2 C(s)¯ uf(p3, σf)/ p4 1 / P − ˚ MψP
cc
/ p2ui(p1, σi), Born terms in s-channels are considered and the contribution from u-channel Born terms is small. ( 2 − 2
√ 3
− 2
√ 3 2 3
)
I=0
,
3 2 1 2 √ 6 2 1 2 1 6 1 √ 6 √ 6 2 1 √ 6
1
I=1/2
I = 0: Ξcc¯ K − Ωccη; I = 1/2: Ξccπ − Ξccη − ΩccK
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 8 / 20
2 −
The interactions in LO ChPT contain Weinberg-Tomozawa terms and Born terms with ground state of doubly charmed baryons exchanging. LLO = ¯ ψcc(i/ D − m0 + gA 2 γµγ5uµ)ψcc. with Dµ = ∂µ + 1 2 [ u†∂µu + u∂µu†] , uµ = iu†DµUu† The axial coupling constant gA is estimated as, |gA| = 0.2
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 9 / 20
2 −
The ground-state doubly charmed baryons are expected to form a fmavor triplet of matter fjelds, ψcc = Ξ++
cc
Ξ+
cc
Ω+
cc
. The light pseudoscalar mesons (π, K, η) are the Goldstone bosons of QCD, U = u2 = ei
√ 2Φ F
with Φ =
1 √ 2π0 + 1 √ 6η
π+ K+ π− − 1
√ 2π0 + 1 √ 6η
K0 K− ¯ K0
−2 √ 6η
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 10 / 20
2 −
NLO terms in ChPT: V(2)(s, t, u) = 4C0 F2 h0 + 2C1 F2 h1 − 2C24 F2 + 2C35 F2 H35(s, t, u) ci = hi 2 ¯ MD , i = 0, 1, 24, 35, where C24 = C2 + C′
4, C35 = C3 + C′ 5, C′ 4 = C4 ¯
M2
ψcc and C′ 5 = C5 ¯
M2
ψcc. ¯
MD and ¯ Mψcc are the averaged masses of the ground state charmed mesons and doubly charmed baryons, respectively. Values of hi have been fjxed from fjtting results of lattice calculation.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 11 / 20
2 −
Bethe-Salpeter equation with on-shell approximation
T = (1 − V · G)−1V, where V = VWT + Vs + V(2). Vs is contribution from baryon exchanging with P-wave excitation in heavy diquark. Neglecting u-channels in Born terms of ground states and excitation states exchanging, contribution of which has been checked and is small.
F-K Guo et al PLB641,278(2006); D.-L. Yao et al EPJC78,310(2018)
M
cc
MeV M
cc
M
cc=MDs
MD M
P cc
MeV, bare pole ( ) in quark model.
D.Ebert et al PRD 66,014008(2002)
M
P cc
M
cc
MeV 3942MeV.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 12 / 20
2 −
Bethe-Salpeter equation with on-shell approximation
T = (1 − V · G)−1V, where V = VWT + Vs + V(2). Vs is contribution from baryon exchanging with P-wave excitation in heavy diquark. Neglecting u-channels in Born terms of ground states and excitation states exchanging, contribution of which has been checked and is small.
F-K Guo et al PLB641,278(2006); D.-L. Yao et al EPJC78,310(2018)
MΞ++
cc
= 3621.4 MeV MΩ+
cc − MΞ+ cc=MD+ s − MD+
MΞP
cc = 3838 MeV, bare pole ( 1
2 −) in quark model.
D.Ebert et al PRD 66,014008(2002)
MΩP
cc ≈ MΩcc + 217MeV ≈ 3942MeV. Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 12 / 20
2 −
Sector I=0,S=-1, Ξcc¯ K-Ωccη. Thresholds: 4120 MeV and 4273 MeV.
20 40 60 Γ [MeV] Ωcc
P,H
Ωcc
P,L
0.0 0.1 0.2 0.3 0.4 0.5 0.6 3900 3950 4000 4050 4100 4150 4200 M [MeV]
λBC λRC MΞcc+MK
_
MΩcc
P
∘
λ
Compositeness：P g
G s s Mpole.
The higher pole contains 55-80 % of
ccK.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 13 / 20
2 −
Sector I=0,S=-1, Ξcc¯ K-Ωccη. Thresholds: 4120 MeV and 4273 MeV.
20 40 60 Γ [MeV] Ωcc
P,H
Ωcc
P,L
0.0 0.1 0.2 0.3 0.4 0.5 0.6 3900 3950 4000 4050 4100 4150 4200 M [MeV]
λBC λRC MΞcc+MK
_
MΩcc
P
∘
λ
Compositeness：P = −g2 ∂G
∂s
pole.
The higher pole contains 55-80 % of Ξcc¯ K.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 13 / 20
2 −
Study on isospin violated decay width is a good way to understand hadronic structure. Mass difgerences of intermediate particles in loops in particle basis and π0 − η mixing contribute to decay width.
π0 − η mixing
˜ π0 = π0 cosϵπ0η + η sinϵπ0η, ˜ η = −π0 sinϵπ0η + η cosϵπ0η. where ϵπ0η = √ 3 4 md − mu ms − ˆ m with ˆ m = (mu + md)/2,
md−mu ms− ˆ m = 0.012 ± 0.001
F.K. Guo et al PLB66(2008) Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 14 / 20
Sector I=0,S=-1, Ξcc¯ K-Ωccη-Ωccπ0
0.0 0.1 0.2 0.3 0.4 20 40 60 80 100 Γ [keV]
(a) Ωcc
P,H
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.0 0.5 1.0 1.5 2.0 2.5 λ Γ [keV]
(b) Ωcc
P,L
Figure: Decay width of Isospin violated process
Decay width of the lower pole is a few keV and the one of the higher pole is larger than 30 keV.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 15 / 20
2 −
Sector I=1/2,S=0, Ξccπ-Ξccη-ΩccK
▲ ▲ ▲ ▲ ▲ ▲ ▲ ■ ■■ ■ ■ ■ ■
3.9 4.0 4.1 4.2 50 100 150 200 250 300 M [GeV] Γ [MeV]
▲
Ξcc
P,1 ■
Ξcc
P,2
P,3
λ=0 λ=0.6 λ=0 λ=0.6 λ=0.6 λ=0
Figure: Trajectories of the three resonant poles in the (S, I) = (0, 1/2) channel vary with λ value. Central values of LECs and aψccφ are adopted, and ˚ MΞP
cc = 3838 MeV is used.
Thresholds: 3762 MeV, 4176 MeV and 4222 MeV.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 16 / 20
Analogue of DK hadronic molecule D∗
s0(2317): Possibility of two
narrow doubly charmed baryons with JP = 1
2 −, the lower one
corresponds to the normal ccs baryon, while the higher pole to the Ξcc¯ K hadronic molecule. The LECs up to NLO are correlated to those for heavy meson-GBs interactions via HADS, the latter ones have been widely studied and fjxed by lattice simulation. Difgerence: there is an additional s-channel pole contribution. Other analogues: JP = 1
2 −, 3 2 − doubly heavy baryons.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 17 / 20
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 18 / 20
NLO terms in chiral Lagrangian and low energy constants read T(2)(s, t, u) = 4C0 F2 h0 + 2C1 F2 h1 − 2C24 F2 + 2C35 F2 H35(s, t, u) (1) with H24(s, t, u) = 2h2p2 · p4 + h4(p1 · p2p3 · p4 + p1 · p4p2 · p3) (2) H35(s, t, u) = h3p2 · p4 + h5(p1 · p2p3 · p4 + p1 · p4p2 · p3) (3) G contains a subtraction, a(1GeV) = −2.79+0.04
−0.05.
Matching the value of G at threshold with a regularization of three momentum cut-ofg, qmax ≈ mρ.
Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 19 / 20
Here one makes an analogy to the case of D∗
s0(2317) bounded from DK.
But the contributions from md − mu and electromagnetic term (virtual photons) go in opposite directions.
Ds(2317)
(MD+ − MD0)strong = (2.67 ± 0.30) MeV, (MD+ − MD0)em = (2.10 ± 0.32) MeV
Ξcc
(MΞ++
cc
− MΞ+
cc)strong = (−2.7 ± 1.5) MeV,
(MΞ++
cc
− MΞ+
cc)em = (4.2 ± 2.30) MeV Mao-Jun Yan New spectrum of negative-parity doubly charmed baryons 2019-08-20 20 / 20