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The preliminary result from (K° s   ) spectra in reaction p+A at 10 GeV/c

The preliminary result from (K° s   ) spectra in reaction p+A at 10 GeV/c. , October 2, 2006. Contents Preview Method (, + ) spectrum (K 0 s ,  ) spectra Conclusion. P.Zh.Aslanyan , V.N. Emelyanenko. JOINT INSTITUTE FOR NUCLEAR RESEARCH , YEREVAN STATE OF UNIVERSITY. Preview.

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The preliminary result from (K° s   ) spectra in reaction p+A at 10 GeV/c

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  1. The preliminary result from (K°s)spectra in reaction p+A at 10 GeV/c , October 2, 2006 Contents • Preview • Method • (,+) spectrum • (K0s ,) spectra • Conclusion P.Zh.Aslanyan , V.N. Emelyanenko. JOINT INSTITUTE FOR NUCLEAR RESEARCH, YEREVAN STATE OF UNIVERSITY

  2. Preview The scalar mesons have vacuum quantum numbers and are crucial for a full understanding of the symmetry breaking mechanisms in QCD, and presumably also for confinement. Suggestions that the  (600) and (800) could be glueballs have been made. There are theoretical arguments for why a light and broad (800)(qq or 4-quark state) pole can exist near the K threshold and many phenomenological papers support its existence . The (600) and (800) indeed belong to the same family as the f0(980) and a0(980) mesons (say if the  (600) were composed of 2 or 4 u and d type quarks) then no such mechanism would suppress the decay 0(600)+- or (800) K. The PDG numerous determinations of the pole mass in the neighborhood of 600 MeV. There is believe that experimental groups should look for pole positions in their data analysis, which also include the aforementioned nonlinear effects from S-wave thresholds. The E791 Collaboration reported a light  with mass 797 MeV and width 410 MeV, but uses a Breit–Wigner amplitude . This claim was, however, not confirmed by the CLEO Collaboration. A lighter and very broad  pole is nonetheless possible and should be looked for in future data analyzes. “

  3. Bockmann et al.,Nuclear Physics ,V. B166(1980), No.2. The present data come from exposure of the CERN 2 m hydrogen bubble chamber to + and p beams. The investigation is based on totals of apporximately 330000 + p events at 16 GeV/c and 280000(400000) for pp events at 12(24) GeV/c. Effective mass distribution for K0s+ and K0s- inpp interactions at 12 , 24 GeV/c and -p interactions at 16 GeV/c. The curves represent the fits with the background dashed below K*(892) signals.There are negligible peaks in mass ranges of 720 and 800 Mev/c2. Particles andNuclei, Letters”[114],2002 .The effective mass distribution of +- -combinations from the total statistics of the reactionnp +- at Pn = 5.20 GeV c .The dotted curve is the background taken in the form of a superposition of Legendre polynomials up tothe 10-th degree, inclusive. The effective mass distribution of +- –combinations from total statistics of the reaction np +- at Pn=5.2 GeV/c(JINR HPC). The distribution is approximated by a polynomial background curve and by 3 resonance curves taken in the Breit-Wigner form Fig.. At least 3 states with quantum numbers of 0 –meson 0+(0{++}) have been found at masses of 418, 511 and 757 MeV/c2. The fact low -mass 0-mesons are glueballs is one of the possible interpretations.

  4. 1. PBC method A reliable identification of the above mentioned resonance needs to use 4-detectors and high precision measurements of the sought objects. The bubble chamber is the most suitable instrument for this purpose . The full experimental information of more than 700000 stereo photographsor 106 p+propane events from inelastic interactions are used to select the events with V0 strange particles . The GEOFIT based on the Grind-CERN program is used to measure the kinematics parameter of tracks momenta(P), tg( - depth angle) and azimuthal angle() in the photographs. The relative error of measuring momentum p and the average track length L of charged particles are found to be P/P=2.1%,< L>=12 cm for stopped particles and P/P>=9.8 %, <L>= 36 cm for nonstopped particles. The mean values of measurement errors for the depth and azimuthal angles are equal to tg = 0.0099 ± 0.0002 and  = 0.0052 ± 0.0001 (rad.). The estimation of ionization, the peculiarities of the end track points of the stopped particles (protons, K ) allowed one to identify them. Protons can be identified over the following momentum range: 0.150 P 0.900 GeV/c. In the momentum range P > 0.900 GeV/c protons couldn't be separated from other particles.

  5. 2.1. Identification of  and Ks0 Figures (a,c) and (b,d) show the effective mass distribution of 8657-events with , 4122-events with Ks0 particles and their 2 from kinematic fits, respectively. The expected functional form for 2 is depicted with the dotted histogram. The measured masses of these events have the following Gaussian distribution parameters MK= 497.7± 3.6, s.d.= 23.9 MeV/c2 and M  =1117.0 ± 0.6, s.d.=10.0 MeV/c2. The masses of the observed , Ks0 are consistent with their PDG values. The experimental total cross sections are equal to 13.3 and 4.6 mb for  and Ks0 production in the p+C collisions at 10 GeV/c.

  6. Figure compares the momentum, cos in the c.m. nucleon-nucleon system, transverse momentum(pt) and longitudinal rapidity distributions of  and K0s for experimental events (solid line) and those simulated by the FRITIOF model (broken line)in p+C interactions. From Fig. one can see that the experiment is satisfactorily described by the FRITIOF model.

  7. (+ )spectrum Test method with known resonance. Resonance with similar decay properties*(1382) registered. Decay width is equal to  40 MeV/c2. M/M0.7 % in range of *(1382)invariant mass. Just the cross section of *(1385) production (540 simulated events) can estimated by FRITIOF model which is equal to 0.95 mb (540 simulated events) at 10 GeV/c for p+C interaction.

  8. ( Ks0 ) - spectra The total experimental background has been obtained by three methods. In the first method, the experimental effective mass distribution was approximated by the polynomial function after cutting out the resonance ranges because this procedure has to provide the fit with 2=1 and polynomial coefficient with errors less than 30 %. This distribution was fitted by the six-order polynomial. The second of the randomly mixing method of the angle between K0s and  for experimental events is described in Then, these background events were analyzed by using the same experimental condition and the effective mass distribution. The third background method has been obtained by using FRITIOF model with experimental canditions (FRITIOF, H. Pi, Comput. Phys.Commun. 71,173, 1992). ( K0s) was fitted by the polynomial function (Figure). The analysis done by two methods has shown that while fitting these distributions had the same coefficients (with 30 % errors) and order of polynomial.

  9. The investigation is based on totals of approximately 106 p+ propane inelastic events at 10 GeV/c. The effective mass distribution of K0s+ -combinations from the total statistics of the reactionpA at Pp= 10GeV/ c .The solid curve is the background taken in the form of a superposition of Legendre polynomials up tothe 8-th degree, inclusive. The dashed histogram is the background by FRTIOF. The invariant mass has significant enhancement in range of 890 Mev/c2(from PDG). There are peaks in mass ranges of 720(4.6), 800(4.2) and 1060(7.3) Mev/c2. There is negligible peak in mass ranges of 1430 Mev/c2(PDG). The possible interpretation of the peak in mass ranges of 1060 Mev/c2 is sum of reflections from well known resonances in mass ranges of (1410-1430 Mev/c2) by channel of K(892)(K0s). know

  10. The effective mass distribution of K0s+ -combinations after cut of momentum P<0.9 GeV/c. It is removed from background combinations with protons.The dashed curve is the background taken in the form of a superposition of Legendre polynomial up tothe 6-th degree, inclusive. The dashed histogram is the background by FRTIOF. in Figure(a) the effective mass distribution is presented with large scale (33 MeV/c2). In this case there are significant enhancements in mass ranges of 720 and 890 MeV/c2.

  11. The solid curveis the sum of 2BW and background (black) taken in the form of a superposition of Legendre polynomial up tothe 6-th degree. The dashed curve(red) is the background by polynomial without range of 0.75< MK <0.98 MeV/c2 when a 1BW function was used.

  12. K0s- - spectra The effective mass distribution of K0s- -combinations from the total statistics of the reactionpA at Pp= 10GeV/ c .The solid curve is the background taken in the form of a superposition of Legendre polynomials up tothe 6-th degree, inclusive. The dashed histogram is the background by FRTIOF.The invariant mass has significant enhancement in range of 890 Mev/c2(K*(892) PDG). There are peaks in mass ranges of 730 and 780 Mev/c2. in Figure(a) the effective mass distribution presented with large scale (33 MeV/c2). In this case there are significant enhancements in mass ranges of 730 and 890 MeV/c2.

  13. The solid curveis the sum of 2BW and background (black) taken in the form of a superposition of Legendre polynomial up tothe 6-th degree. The dashed curve (red) is the background by polynomial without range of 0.75< M K <0.96 MeV/c2 when a 1BW function was used.

  14. Conclusion • A number of same peculiarities were observed in the invariant mass spectra of • (K0S+) and (K0S-) subsystems for pA  (K0S ) X reactions at momentum of 10 GeV/c by using PBC data in ranges of:(710-1730), (780-810), (885-895) and (1050-1080)MeV/c2. • The invariant mass of + spectra has significant enhancement in range of 890 Mev/c2 (*(1395) from PDG). Test method. • The invariant mass of K0sspectra has significant enhancement in range of 890 Mev/c2 (K*(892) from PDG). • The preliminary interpretation of the peak in mass ranges of 1060 Mev/c2 is sum of reflections from well known resonances in mass ranges of (1410-1430 Mev/c2) by channel of K(892)(K0s). • The preliminary result of observation (in Table) are presented for K0 spectra with mass of 720 S.D. (>4.1 S.D) , 780 MeV/c2 (>2.5 S.D.) and width >29 MeV/c2 , 12 MeV/c2 respectively. The17-th SPIN Physics Symposium, Kyoto Japan, October 2,2006

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