Search for narrow six-quark states

Search for narrow six-quark states

L.V. Fil’kov,(1) V.L. Kashevarov,(1,2) M. Ostrick(2)

(1) P.N. Lebedev Physical Institute , Moscow

EMIN - 2012

(2) Institut fur Kernphysik, University of Mainz

Supernarrow six-quark states

D N N ~ 10 100 MeV

6-quark states, decay of which into two nucleons is forbidden by thePauli exclusion principle.

M < 2mN + m D → + NN

+ d

* Wide dibaryons : ~ 10 100 MeV* Narrow dibaryons : ~ 1 1 MeV* Supernarrow dibaryons : << 1 keV

6-quark statenucleon (dibaryon)

eV

(-1)T+S P = +1

1. A construction of an adequate QCD model.

2. Astrophysics: an evolution of compact stars.

3. Quark-gluon plasma: specific signals of a production of QGP with the big baryon dencity.

4. Nuclear physics: a formation of SND-nuclei; a region stability of neutron-rich nuclei.

1. P.J.G. Mulders et al. (1980)

MIT bag model: D(T=0; JP = 0─, 1─, 2─; M=2110 MeV), D(1; 1─; M=2200 MeV)

M > 2mN + m D NN

2. V.B. Kopeliovich (1993)

Chiral soliton model: D(T=1; JP = 1+; M 1940 MeV),≃

D(0; 2+; M 1990 MeV)≃3. T. Krupnovniskas et al. (2001)

Canonically quantized biskyrmion model: M < 2mN + m

one dibaryon with J=T=0, two dibaryons with J=T=14. L.V. Fil’kov (2003)

Mass formula for SND: T=1, J=1±

M=1904 (J=1-), 1924 (1+), 1943 (1-),

1962 (1+), 1982 (1-), 2001 (1+)

D(T=0, JP=0+ ), D(0, 0─), D(T=1, J =1+), D(1,1─)

D N

NX

d if T = 0

31S0 if T = 1X = {

M(GeV)

1.90

1.91

1.93

1.96

1.98

2.00

(1,1+

) (eV)

0.51

1.57

6.7 25.6

48 81

(1,1─

) (eV)

0.13

0.39

1.67

6.4 12 20

p1+d→p2+pX1

MpX1: ±, ±, ±

SD: 6.0 7.0 6.3

< 5 MeV (experimental resolutions) if X1 = n → MX1 =

mn

if X1 = + n → MX1

mn

Simulation of mass MX1 spectra gave:MX1 = 965, 987, 1003 MeV

Experiment:MX1= ±, ±, ±

X1= + n

L.V. Fil’kov, V.L. Kashevarov, E.S. Konobeevski et al. Phys. Rev. C61, 044004

(2000); Eur.Phys.J. A12, 369 (2001); INR (Moscow)

pp d1 pp

A.S. Khrykin et al. Phys. Rev. C 64, 034002 (2001)

Tp= 216 MeV, E10 MeV,

MMeV T=2

Uppsala pp-bramsstralung data(H. Calen, et al., Phys. Lett. B427, 248 (1998)):

upper limit 10 nb.

p d p pX p d p dX1

Research Center for Nuclear Physics (Japan)H. Kuboki et al. Phys. Rev. C 74, 025203 (2006)

1. No resonance structure in the missing mass spectra of pX and dX1 was observed.

2. No resonance structure in missing mass spectra of X. (It is at variance also with the results of the work of B. Tatischeff et al. (Phys. Rev. Lett. 79, 601 (1997))

INR: beam intensity 0.1 nA RCNP: beam intensity (15 – 20) nA

A. Cichocki, PhD (2003)

B. Norum et al. (LEGS)

E= 210 – 340 MeV

P= 99%

= 25 – 14 nb

SEARCH FOR NARROW SIX-QUARK STATES IN THE REACTIONS d NN

The energy and angular distributions of the nucleons from

the decay of SNDs

The distributions over the angle between the final nucleons and over the relative difference of energies of these nucleons

M=1904 MeV M=1926 MeV M=1942 MeV M=1982 MeV

The energy and angular distributions of the photons from the decay of SNDs

M=1904 MeV M=1926 MeV M=1942 MeV M=1982 MeV

Background

d → D(1,1) , (b,c,d) for M=1904, 1942, 2000 MeV

d → D(1,1)

d → D(1,1) , (b,c,d) for M=1904, 1942, 2000 MeV

d → D(1,1)

GEANT simulation of SND

GEANT simulation of p andn mass spectrum; (a) – without an influence of the detectors.

(a)

(b)

(c)

d0 +pnMAMI (Preliminary)

MM(,0) – md (MeV)

Red lines are SND peak positions from INR experiment

V. Kashevarov, 8th Crystal Ball@MAMI Collaboration Meeting, Glasgo, March 27-29, 2006

Conclusion

d → 0 D(1,1) , (b,c,d) for M=1904, 1942, 2000 MeV

d → 0 D(1,1)

The Two Arm Mass Spectrometer (TAMS). S0, S1, S2, and S3 are start

detectors; F0, F1, F2, and F3 are stop E detectors; D0 is a BGO detector;

D1, D2, and D3 are full absorption E detectors.

(a) – 33o, (b) – 35o , (c) – 37o

GEANT simulation of p mass spectra.

JLAB

A. Cichocki, PhD (2003) B. Norum et al. (LEGS)

E210-340 MeV

=25-14 nb

P99%

B. Norum et al. (LEGS)

E=210-340 MeV=90

=25 -14nb

A.Cichocki, PhD (2003)

P= 99%