1. Production rates of Strange and Charmed baryons at Belle 1 string @  s = 10.52 GeV Nuclear physics consortium

2. Production rate of hadrons 2 Slope of meson (qq bar ) is different from baryons (qqq). Slope depends on quark counting “4 or 5-quark state” do not lie on “3-quark state”?  (1405), pentaquark,    Production rate  had /(2J+1)  exp(-  m h ) due to linear potential m h (mass of hadrons)[GeV]  /  had /(2J+1)

3. 3 Mass of baryons (GeV) Previous data deviate ARGUS  s=10.5 GeV Belle  (g.s.)/  (1520) deviate in LEP  good di-quark > bad di-quark?  (1520)[3/2 - ] deviates in ARGUS  [3/2 - ] state is special?  L=0 ≠ L=1 ?   (1520) [3/2 - ]  c*(2625)[3/2 - ]  (1405) [1/2 - ]  c*(2595)[1/2 - ] LEP  s=92 GeV R.L.Jaffe, Phys.Rept.409:1-45,2005 Error bar in ARGUS is large  More precise data No series of charmed baryon  First systematic measurement of production rate for charmed baryons.

4. 4 q q q Interaction between quarks Diquark correlations  Charmed baryon (  c [udc]  c  [udc]) Diquark correlation is enhanced by weak Color Magnetic Interaction with a heavy quark m u, m d << m c  diquark + quark (qq) (Q) qq ( ) S=0 “good” diquark qq ( ) S=1 “bad” diquark Q q Diquark picture  Strange baryons (  uds  [uds]) m u, m d ≈ m s  (qqq) uniform

5. Strange baryon & Charmed baryon 5 ,   c,  c [qqs] uniform diquark + Quark [qq] [c] Strange baryons Charmed baryons  c >  c good di-quark > bad di-quark due to strong attractive force of good diquark  u d s u d s cc L L u d S=0 S=1 S=0S=1

6. 6 Systematic study of baryons to search for “exotic” baryons in strange and charmed baryons. Information on diquark picture of charmed baryons in contrast with strange baryons.    c,  c *,  c,  c * First systematic measurement for series of charmed baryons. It is interesting and important to look at the tendency of many baryons by precise measurement. Belle data, well constructed detectors and good statistics. In this work

7. Silicon Vertex Detector Central Drift Chamber Aerogel Cerenkov Time Of Flight CsI calorimeter S.C. solenoid 1.5T K L μ system 8GeV e - 3.5GeV e + Data of Belle Integrated luminosity 79.366 fb -1 @  s = 10.52 GeV 702.623 fb- 1 @  s = 10.58 GeV ϒ(4S) 7

8. Good vertex reconstruction SSD placed in 3cm/2cm from Interaction point (IP), and low materials. Resolution of reconstructed vertex for B  J/Psi Ks is about 80  m. Good for hyperon (long life) reconstruction. Profile of interaction point (IP) 8

9. Hyperon reconstruction xx IP Interaction point p  momentum vector of  Decay processes   p  -                 or       c  =7.89cm IP     c  = 4.91cm / 2.64cm  c  = 7.89cm  p   + for  c 0 Decay processes            c       9

10.  Mass spectrum of   +  bar = 373.9 ± 0.5 pb “Inclusive” total cross section Feed down processes from higher states d  /dx p Xp  bar preliminary 10

11. Mass spectra real data events in 0.3 < x p <0.4   (1192)    (BR~100%)   (1383) +     BR=87%) 11

12. “Inclusive” cross sections vs. x p 12   +c.c   +c.c. Xp preliminary d  /dx p   +  0 = 97.0 ± 1.5 pb   +  * = 33.2 ± 2.4 pb Inclusive total cross section

13. direct cross section of  feed-down were subtracted from inclusive cross sections  Isospin symmetry was assumed for   and  production cross-sections. Result (inclusive) 13

14. direct  0 and  *+ production feed-down were subtracted from inclusive cross sections  Isospin symmetry was assumed for   and  production cross-sections. Result   + c.c. (direct) : 33.2 ± 2.4 pb   + c.c. (inclusive)  0.4 ± 0.06 pb  (1520) + c.c. = 32.8 ± 2.4 pb 14

15.  (1520) 15 Select p and K - from IP with cuts for distance from IP   (4S) data ▽▽ Continuum data Y / anti-Y preliminary BR=22.5%  (1520)  pK  Mass spectrum of 

16. Direct cross section  (1520) 16  (1520)+c.c. (direct) = 15.3 ± 0.5 pb inclusive – 0.34 ± 0.17 pb  c + = 15.0 ± 0.26 pb

17. Mass spectrum of   and   17 

18. Cross sections of  and  18   bar inclusive cross section = 25.55 +- 0.64 pb  +  bar inclusive cross section = 1.15 +- 0.32 pb   (4S) data ○○ ＠ 10.52, Continuum data Y / anti-Y preliminary

19.  c      +c.c. 19  x BR (     ) + c.c. = 0.04 0.003 pb  c    X = 0.2 pb BR 1.25±0.5% for   X 0.25±0.12% for     by phenomenological calculation (ref. PDG) Event rate / L int. Counts preliminary Mass [GeV] xpxp

20.  c   c *     c   and  c  Decay process analyzed in this work  c   pK -  +  c * (2625)   c   +    c     c     c  (2520)   c    + c.c. cc Mass plot Mass spectrum of  p  20

21. 21  c     (4S) data ▽▽ Continuum data Y / anti-Y XpXp d  /dx p (nb) preliminary  c (2595) +  c (2625) +  c   Mass spectrum

22. 22  c (2455) 0  c (2520) 0  c    decay processes Exclude in analysis  c * (2595) +   c   +    c * (2625) +   c   +  

23. 23   (4S) data ▽▽ Continuum data Y / anti-Y  c   preliminary  c   preliminary Cross sections

24. direct  c and  c production 24  c  + c.c. (direct) = 189 ± 66 pb inclusive  (17.9 ± 6.0 pb ) x 3  c   + c.c.  18.8 ± 6.4 pb) x 3  c   + c.c.  ( 31.3 ± 10 pb)  c   + c.c.  47.6 ± 16.2 pb  c   +c.c. (direct) = 17.9 ± 6.0 pb  c   + c.c. (direct) = 18.8 ± 6.4 pb  c   + c.c. (direct) = 31.3± 10 pb Λc(2595) and Λc(2775) feed down are included.

25. Result and discussion 25 Previous Belle work This work (very preliminary) ARGUS  Mass dependence strange ≠ charm not lie on the same line  Large discrepancy to ARGUS on , and  * treatment of feed down?  Deviation of     is not clear.   < ,     sss  with “  “  no good diquark  /  had /(2J+1) Mass of baryons (GeV)

26. 26 Charmed baryons do not lie on “one” line. J p : no measurement or not well measured quark-model prediction  c >  c  good diquark > bad diquark Large rate of  c (2625)[3/2 - ](L=1 state) Prefer [3/2-] or L=1? Why? Rate of  )[3/2 - ] is not large. Rates of  c (2595)[1/2 - ](L=1 state) and  (1405)[1/2-] are “key”.  c : no measurement of BR a plot with BR(0.24+-0.12%) by the phenomenological calculation. Production rate  BR  c (g.s)[1/2 + ]  c (2625)[3/2 - ]  c 0 (2455)[1/2 + ]  c 0 (2520)[3/2 + ]  c (2800)[? ? ] use 3/2  /  had /(2J+1) Mass of baryons (GeV) Charmed baryons  c Results and discussion Very preliminary

27. States 27  [1/2 + ]  (1405) [1/2 - ]  (1520) [3/2 - ]  [1/2 + ]  [3/2 + ]  [1/2 + ]  [3/2 + ]  [3/2 + ]  c + [1/2 + ]  c (2595) + [1/2 - ]  c (2625) + [3/2 - ]  c (2455) [1/2 + ]  c (2520) [3/2 + ]  c [1/2 + ]  c *  c [1/2 + ]  c * On going Unknown J, BR

28. M(  ) 28  (1530)  c

29. Production rates 29  /  had /(2J+1) Mass – Mass(g.s.) [GeV/c 2 ]

30. Summary We measure production rates of strange and charmed baryons at  s = 10.52 GeV at Belle. “Systematic” study provides information on quark structure of hadrons. Configuration and performance of Belle detector is good for long-life particles like  and  We observed ‘charmed baryons do not lie on one line’. Can we explain by a diquark picture? Feed down processes Further study of many baryons with various spin-parity is interesting to see their quark structures. 30