V. V. Anisovich

Nonet classification of scalar/isoscalar resonances below 1900 MeV: the existence of an extra scalar state in the region 1200–1600 MeV

Abstract A classification of the IJ PC = 00 ++ mesons is performed on the basis of the K -matrix analysis of meson spectra in the reactions: (i) GAMS data on πp → π 0 π 0 n , ηηn , ηη ′ n [D. Alde et al., Z. Phys. C 66 (1995) 375; A.A. Kondashov et al., Proc. 27th Intern. Conf. on High Energy Physics, Glasgow (1994) 1407; Yu.D. Prokoshkin et al., Physics-Doklady 342 (1995) 473; A.A. Kondashov et al., Preprint IHEP 95-137, Protvino (1995); F. Binon et al., Nuovo Cim. A 78 (1983) 313; A 80 (1984) 363]; (ii) Crystal Barrel data on p p ( at rest ) → π 0 π 0 π 0 , π 0 π 0 η, π 0 ηη [V.V. Anisovich et al., Phys. Lett. B 323 (1994)233; C. Amsler et al., Phys. Lett. B 342 (1995) 433]; (iii) CERN-Munich data on πp → π + π − n [B. Hyams et al., Nucl. Phys. B 64 (1973) 134]; (iv) BNL data on πN → K K N [S.J. Lindenbaum and R.S. Longacre, Phys. Lett. B 274 (1992) 492; A. Etkin et al., Phys. Rev. D 25 (1982) 1786]. The analysis points to the existence of four comparatively narrow scalar resonances which correspond to the following poles of the scattering amplitude (in MeV): (1015 ± 15) − i (43 ± 8), (1300 ± 20) − i (120 ± 20), (1499 ± 8) − i (65 ± 10) and (1780 ± 30) − i (125 ± 70). The scattering amplitude also has a fifth pole f 0 (1530 −250 +90 ) at the complex mass (1530 −250 +90 − i (560 ± 140). The masses of the K -matrix poles (bare states) are at 720±100 MeV, 1230±50 MeV, 1260±30 MeV, 1600±50 MeV and 1810±30 MeV. The quark content of the bare states is analyzed using the values of their couplings to the ππ, K K , ηη and ηη′. It is shown that one of the bare states in the mass region 1200–1600 MeV is superfluous for the q q classification and should be considered as the lightest glueball.

Two-resonance structure of the (I JPC = 0 0++) ππ-amplitude in a mass region around 1 GeV

Abstract The structure of the ( I = 0, J PC = 0 ++ ) S -wave ππ-amplitude up to an invariant energy of 1.15 GeV is determined from a simultaneous analysis of the GAMS data on the π − p → π 0 π 0 n reaction in a set of 4-momentum transfer squared intervals, together with the S -wave ππ phase shift (CERN-Munich data) and the Crystal Barrel data on the p p → π 0 π 0 π 0 , p p → ηηπ 0 and p p → ηπ 0 π 0 annihilations at rest. The analysis shows the existence of two resonances near the K K threshold: a narrow one with a mass of 987 MeV and a width of 80 MeV, and a wide one with a mass of 1160 MeV and a width about 900 MeV. These physical states appear as a result of mixing of two original states with masses ≈ 800 MeV and ≈ 1200 MeV. The first one is a candidate for the σ-resonance.

0++-glueball/qq-state mixing in the mass region near 1500 MeV

Abstract Based on the results of the K -matrix fit of the ( IJ PC = 00 ++ ) wave [V.V. Anisovich, Yu.D. Prokoshkin and A.V. Sarantsev, Phys. Lett. B 389 (1996) 388; V.V. Anisovich and A.V. Sarantsev, Phys. Lett. B 382 (1996) 429], we analyze the analytic structure of the amplitude and q q /glueball content of resonances in the mass region 1200–1900 MeV, where an extra state for q q -systematics exists being a good candidate for the lightest scalar glueball. Our analysis shows that the pure glueball state is dispersed over three resonances: f 0 (1300), f 0 (1500) and f 0 (1530 −250 +90 ), while the glueball admixture in f 0 (1750) is small. The broad resonance f 0 (1530 −250 +90 ) is the descendant of the lightest pure glueball. The mass of the pure glueball is 1630 ± 30 70 MeV, in agreement with Lattice calculation results [F.E. Close and M.J. Teper, On the lightest scalar glueball, preprint RAL-96-040 (1996); G.S. Bali et al., Phys. Lett. B 309 (1993) 378; J. Sexton, A. Vaccarino and D. Weingarten, Phys. Rev. Lett. 75 (1995) 4563].

Quark-antiquark states and their radiative transitions in terms of the spectral integral equation: Charmonia

AbstractEarlier by the authors (Yad. Fiz. 70, 68 (2007)), the bƃ states were treated in the framework of the spectral integral equation, together with simultaneous calculations of radiative decays of the considered bottomonia. In the present paper, such a study is carried out for the charmonium % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmWu51MyVXgatC% vAUfeBSjuyZL2yd9gzLbvyNv2CaeHbd9wDYLwzYbItLDharyavP1wz% ZbItLDhis9wBH5garqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbb% L8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpe% pae9pg0FirpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaam% aaeaqbaaGcbaGaeiikaGIaem4yamMafm4yamMbaebacqGGPaqkaaa!3F33!

Decay

(c\bar c)

: analysis in the non-relativistic quark model approach

states. We reconstruct the interaction in the c-c sector on the basis of the data for the charmonium levels with JPC = 0−+, 1−−, 0++, 1++, 2++, 1+− and radiative transitions ψ(2S) → γχc0(1P), γχc1(1P), γχc2(1P), γχc(1S) and χc0(1P), χc1(1P), χc2(1P) → γJ/ψ. The c-c levels and their wave functions are calculated for the radial excitations with n ≤ 6. Also, we determine the c-c component of the photon wave function using the e+e−-annihilation data: e+e− → J/ψ(3097), ψ(3686), ψ(3770), ψ(4040), ψ(4160), ψ(4415) and perform the calculations of the partial widths of the two-photon decays for the n = 1 states ηc0(1S), χc0(1P), χc2(1P) → γγ and n = 2 states ηc0(2S) → γγ, χc0(2P) → γγ. We discuss the status of the recently observed c-c states X(3872) and Y(3941): according to our results, the X(3872) can be either χc1(2P) or ηc2(1D), while Y(3941) is χc2(2P).

Observation of the tensor glueball

AbstractWe demonstrate the possibility of a good description of the processes φ(1020) → γππ and φ(1020) → γf0(980) within the framework of the nonrelativistic quark model assuming f0(980) to be a dominantly quark-antiquark system. Different mechanisms of the radiative decay, that is, the emission of a photon by the constituent quark (additive quark model) and charge-exchange current, are considered. We also discuss the status of the threshold theorem applied to the studied reactions, namely, the behavior of the decay amplitude at Mππ→mφ and