e-mail: [email protected]

S.V. Afanasiev,1 A.S. Artiomov,1 R.N. Bekmirzaev2, D.K. Dryablov,1 Z.A. Igamkulov,1 V.I. Ivanov,1 A.Yu. Isupov,1 D.M. Jomurodov,1 A.I. Malakhov,1

V.Matousek3, M.Morhac3 A.I. Lebedev,4 A.I. L’vov,4 L.N. Pavlyuchenko,4 E.B. Plekhanov1, V.V. Polyansky,4 S.S. Sidorin,4 G.A. Sokol4, M.U. Sultanov5, I.Turzo3

"Search Results for Eta-Mesic Nuclei in the d+C Reaction in JINR"

E-mail: [email protected]

Hadron Structure 2011

[email protected]á Štrba, June 30th

LHEP JINR Dubna

•The properties of hadrons in nuclear medium are one of the interesting topics of the modern hadron and nuclear physics. All nuclei have essentially smaller mass than sum of masses all neutrons and the protons formed nuclei. The difference of masses is a result of strong interaction between hadrons which formed composite system. It is possible to assume, that particles, distinct from nucleons such as an - meson, in nuclear medium will have smaller mass than in a free state.

Motivation


Tatranská Štrba, June 30th

• a new field in studies on nuclear and particle physics.• new data on the -meson and the S11(1535) resonance interactions with nucleons • determination of the energy levels E_g (S11) and E_g() and their widths g(S11) and g() in

the -nucleus• determine mass shift m(S11) and m() in the nuclear medium• A possibility to perform studies on physics of - mesic nuclei at the JINR nuclotron internal

beam reaction p+A n+p+ (A - 1) or d+A n+p+n+ (A - 1)• elementary process p+n* n+S+

11 (1535)* n+ p + *

Physical aims

[email protected]


K. Tsushima Nuclear Physics A670 (2000) 198c-201 c ,“Study o f , , ' and D--mesic nuclei”

K. Tsushima , D.H. Lu , A.W. Thomas, K. Saito Physics Letters B 443 1998 26–32,

“Are - and -nuclear states bound.”

A. I. L'VOV nucl-th/9809054PRODUCTION AND DECAY OF ETA

-MESIC NUCLEI

Proposed mass shift for S11

m(S11) = (24÷30)η + (8)N =30-40 MeV In nuclear medium



Formation of anη mesic nucleus and its decayvia emission of back-to-back

nucleon-pion pairs.

Photoproduction of mesons from nuclei- In-medium properties of hadrons

B. Krusche,nucl-ex/0411033


[email protected]

Formation, evolution an decay• Proposed formation in NN interaction

p+Ap+n+ (A - 1) (13C- prefer ) n+An+p+ (A - 1)

• Investigate d+A1 A2(S11) +p+...• Evolution in the elementary process

S11(1535)* N + • Decay to the -N, N-N and - channels

0.9

0.1

10-5



Scheme of the resonance formationIn the elemental NN interaction produced

or mesons at 180o.

N(1535)S11 I(JP)=1/2 ( 1/2- ) L(,) =0Mass m=1520 to 1550 (1535) MeVFull width =100 to 250 (150) MeV

L.C.Liu Phys. Rev. C 40 p.832



Bounding energy

Pp = Pd

p+A d+ p=0+(A-1)p=0d+A t+ p=0 +(A-1)p=0

Pd = PtEd = 2.22MeV Et = 6.25MeV

1) -meson production 2) To produce stable nucleus-rest from target3) Effective capture of the meson4) To measure the products of decay

13C +d= 12C+t+QQ=1.3 MeV

[email protected]



13C(p,d)12C 13C(d,t)12C

Kinematic of recoil-free transfer reaction

[email protected]

Estimates of the effect yield

Y(p) 1400 eventsY(pp) 230 eventsY(pp) 250 eventsY(ppp) 40 eventsY(pnp) 35 eventsY(pnpp) 6 events

Y(p, -)= L (p12Cp1p2n(A-1)) Br(N) nc f(p/)

- total cross section of eta-nuclei formation;

L - luminosity; - the solid angle; - the probability to have the p pairf(p/) - a geometric fraction;Br(N) - the branching ratio of S11(1535) decay;nc - accelerator cycles per hour;



Production of -mesons in nucleon-nucleon collisionsV. Baru,

PHYSICAL REVIEW C 67, 024002 (2003)

[email protected]

Experimental setup

K-armK1 - Start counterK2 - Trigger & Cherenkov countersK3 - TOF - wallK4 - E-counterK5 - Veto counter

P-armP1 - Start counterP2 - Trigger & Cherenkov countersP3 - TOF - wallP4 - E-counterP5 - Veto counter

Hm - Ring counterN - Neutron detectorAn - Neutron-Veto

FL,FR,BL,BR - Monitors



11

0 0180 10

110 10

350 30

p

p

S p

T MeV

T MeV

Target -1 -- 12C, 8 wires x 8 mkm

Target -2 -- 27Al, 1 mm strip x 10 mkm

Target -3 - - 64Cu, 8 wire x 50 mkm

Target -4 - - 183W, 1 wire x 20 mkm

Target -5 -- 108Ag, 1 mm strip x 20 mkm

Target -6 -- CH2, 1 mm strip x 10 mkm

Construction of the Internal Target StationDimension of the target region

PMT for light control


Tatranská Štrba, June 30th [email protected]

[email protected]

Setup of the experimental RUNThe geometry of the experiment

P-arm K-arm



Reconstracted mass (confidence level > 95%)

2

2

1,2 1 21 2 2 2

1 2

1

1 1

1 1

recon

eff

M T

m mM E E

Effective mass



M5 MeV/c2

TOF0.2 ns

Effective mass formation in dA reaction at the energy 1.5 GeV/nuc

The distributions of the N pair yields are shown in Fig.(a,b) versus Meff of the pair nucleons. The histogram Fig.(b) shows the contamination obtained at the arm angle 170o.The Fig.(a) corresponds to a back-to-back correlation coming from the two-body decay. The histogram Fig.(c) is the result of subtraction the back-to-back (180o) and the contamination measurements.

The ratio of the nucleon pair numbers was N{170}/N{180}=0.42 + 0.08(stat)in the mass region of 1450 < Meff< 1550 MeV/c2.

New data are collected.They are include 105 pairs coming from target in d+Cu and d+C reactions at the energy of primary beam 1.5GeV/nuc and 1.9Gev/nuc.

(a)

(b)

(c)



Counts/10MeV/c2

Effective mass formation in dC reaction at the energy 1.9 GeV/nuc

The yield of proton-pion pairs:



p1700p1800

Y(,p)1.41.8 GeV/c2

Effective mass formation in dC reaction at the energy 2.0 GeV/nuc

New data 2010



Y(,p)2.0 GeV/c2

Best fit is Gaussian + constant Mean 1465.1 MeV Sigma 27.2 MeVConstant 1310

Distribution after rejection

of the constant level

Δ

S11

In medium

Total events under picks ≈2000

N(1535)S11 I(JP)=1/2 ( 1/2- )

L(,) =0Mass m=1520 to

1550 (1535) MeVFull width =100 to

250 (150) MeV

S11

ΔM≈70 MeV

1800

The value of the total cross-section of the process can be found based on the number of inelastic interactions dC, measured on the accounts of monitor telescopes, and the simulation results using the software package GEANT and RQMD.

-3 9A in eff fon in = ( *(N -N ))/( *N ) = 426*32.5*4 /8*10 *1.85*10 =11.6 ± 7.5 b



Inelastic interaction Nin = 1.5÷2.2*109;Solid angle: Ω = 8 10-3 str.Cross-section of dC inelastic interactions at the energy 2.1GeV/nuc.: σin=426 ±22 mbTotal cross-section is : μb

Newest data 2010 give the similar result for p-π pars

[email protected]

Conclusions• Have been measured the energy-sum and the angular

correlation of two nucleon pairs p emitted in the d+C reaction. It have been clearly observed a distinct p back-to-back correlation coming from a target, which may be associated with the signature of two-body final state.

• Data analyses are shown resonance structure formed in the target at the energy region of primary beam 1.5-2.0 GeV/nucl.

• The resonance is shifted to small masses an shift has value around 70 MeV and width of the rsonance is 63 MeV. It disagree theoretical predictions.

• The value of the total cross-section is estimated 10b.





New proposal for η–nuclear study on nuclotron.

d+A1 A2(S11) -+p+...

d+A1 A2(S11) ++n+...

d+A1 A2(η+d*) p +n+...

η+d p +n



Collaboration

S.V. Afanasiev, A.S. Artiomov, D.K. Dryablov, Z.A. Igamkulov, V.I. Ivanov, A.Yu. Isupov, A.I. Malakhov,1 E.B. Plekhanov

Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia

V.Matousek, M.Morhac, I.TurzoInstitute of Physics, Slovak Academy of Sciences, Slovak republic

S. VokálJ. Vrláková, A. Kravčáková, A. Dirner, M. Špavorová, Faculty of Science, University of P.J. Šafárik, Košice, Slovak republic

A.I. Lebedev, A.I. L’vov, L.N. Pavlyuchenko, V.V. Polyansky, S.S. Sidorin, G.A. Sokol, Lebedev Physical Institute, Leninsky Prosect 53, Moscow 117924, Russia

D.M. Jomurodov, R.N. Bekmirzaev, Jizzakh State Pedagogical Institute, Uzbekistan

M.U. Sultanov, Samarkand State University, Uzbekistan

[email protected]

Thank you for attention!





cMeVPN N /227,

The SCAN spectrometer can register only tail of Δ-resonance. Momentum of protons is limited Pp>230 МэВ/с.



Numerical calculation

p+A d+ p=0+(A-1)p=0d+A t+ p=0 +(A-1)p=0

d+A 3He+ p=0 +(A-1)p=0

(p)(p)

(3He)

e-mail: [email protected]

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