共查询到20条相似文献,搜索用时 15 毫秒
1.
V. V. Anisovich V. A. Nikonov 《The European Physical Journal A - Hadrons and Nuclei》2000,8(3):401-404
In the framework of the dispersion relation N/D-approach, we restore the low-energy
(IJ
PC = 00+ +)-wave amplitude sewing it with the previously obtained K-matrix solution for the region 450-1900 MeV. The restored N/D-amplitude has a pole on the second sheet of the complex-s plane near the
threshold, that is the light -meson.
Received: 21 February 2000 / Accepted: 20 June 2000 相似文献
2.
Gui-Jun Ding Rong-Gang Ping Mu-Lin Yan 《The European Physical Journal A - Hadrons and Nuclei》2006,28(3):351-360
X(1835) has been treated as a baryonium with sizable gluon content, and to be almost flavor singlet. This picture allows us
to rationally understand X(1835) production in J/ψ radiative decays, and its large couplings with pˉ, η′ππ. The processes ϒ(1S) → γX(1835) and J/ψ → ωX(1835) have been examined. It has been found that Br(ϒ(1S) → γX(1835))Br(X(1835) → pˉ) < 6.45×10-7, which is compatible with CLEO's recent experimental result (Phys. Rev. D 73, 032001 (2006) hep-ex/0510015). The branching fractions Br(J/ψ → ωX(1835)), Br(J/ψ → ρX(1835)) with X(1835) → pˉ and X(1835) → η′π+π- have been estimated by the quark-pair creation model. We show that they are heavily suppressed, so the signal of X(1835) is very difficult, if not impossible, to be observed in these processes. The experimental checks for these estimations
are expected. The existence of the baryonium nonet is conjectured, and a model-independent derivation of their production
branching fractions is presented. 相似文献
3.
The lattice QCD studies indicate that the critical temperature T
c ≃ 260-280 MeV of the deconfinement phase transition in quenched QCD is considerably smaller than the lowest-lying glueball
mass m
G ≃ 1500-1700 MeV, i.e., T
c ≪ m
G. As a consequence of this large difference, the thermal excitation of the glueball in the confinement phase is strongly suppressed
by the statistical factor e
-mG/Tc ≃ 0.00207 even near T ≃ T
c. We consider its physical implication, and argue the abnormal feature of the deconfinement phase transition in quenched QCD
from the statistical viewpoint. To appreciate this, we demonstrate a statistical argument of the QCD phase transition using
the recent lattice QCD data. From the phenomenological relation between T
c and the glueball mass, the deconfinement transition is found to take place in quenched QCD before a reasonable amount of
glueballs is thermally excited. In this way, quenched QCD reveals a question “what is the trigger of the deconfinement phase
transition ?”
Received: 18 November 2002 / Accepted: 4 February 2003 / Published online: 29 April 2003 相似文献
4.
5.
D. Ebert M. Nagy M. K. Volkov V. L. Yudichev 《The European Physical Journal A - Hadrons and Nuclei》2000,8(4):567-576
Ground-state scalar isoscalar mesons and a scalar glueball are described in a U(3)×U(3) chiral quark model of the Nambu-Jona-Lasinio (NJL) type with 't Hooft interaction. The latter interaction produces singlet-octet
mixing in the scalar and pseudoscalar sectors. The glueball is introduced into the effective meson Lagrangian as a dilaton
on the base of scale invariance. The mixing of the glueball with scalar isoscalar quarkonia and amplitudes of their decays
into two pseudoscalar mesons are shown to be proportional to current quark masses, vanishing in the chiral limit. Mass spectra
of the scalar mesons and the glueball and their main modes of strong decay are described.
Received: 14 July 2000 / Accepted: 31 July 2000 相似文献
6.
This paper is a sequel of a previous one (Scalar mesons in a chiral quark model with glueball, Eur. Phys. J. A 8, 567 (2000)) where an attempt to construct an effective U(3)×U(3)-symmetric meson Lagrangian with a scalar glueball was made. The glueball was introduced by using the dilaton model on
the base of scale invariance. The scale invariance breaking because of current quark masses and the scale anomaly of QCD,
reproduced by the dilaton potential, was taken into account. However, in the previous paper, the scale invariance breaking
because of the terms like h
φφ2 and h
σ
, where φ and are the pseudoscalar and scalar isosinglets, was not taken into account. These terms are produced by the part of the 't Hooft
interaction that is connected with gluon anomalies. Allowing for the scale invariance breaking by these terms has a decisive
effect on the quarkonium-glueball mixing and noticeably changes the widths of glueball strong decays. Taking account of this
additional source of the scale invariance breaking and its implications are the subject of the present work. It is also shown
that in the decay of a glueball into four pions, the channel with two ρ-resonances dominates.
Received: 11 January 2001 / Accepted: 25 January 2001 相似文献
7.
8.
We investigate η- mixing in infrared regularized U(3) chiral perturbation theory by calculating the η and masses up to one-loop order. From this analysis it becomes obvious that even at leading order η--mixing does not obey the usually assumed one-mixing-angle scheme if large N
c counting rules are not employed.
Received: 12 March 2001 / Accepted: 4 July 2001 相似文献
9.
We investigate the spin-3/2 baryons in the 27-plet based on flavor SU(3) symmetry. For J
p = 3/2+, we find all the candidates for non-exotic members. For J
p = 3/2-, we predict a new non-exotic member Λ(1780). Fitting the mass spectrum and calculating the widths of the members show an
approximate symmetry of the 27-plet of SU(3). We find that the exotic members have relatively large widths and the Ξ(1950) has spin and parity J
p = 3/2-. The possibility of assigning the non-exotic candidates to an octet is also analyzed. 相似文献
10.
N. I. Kochelev T. Morii B. L. Reznik A. V. Vinnikov 《The European Physical Journal A - Hadrons and Nuclei》2000,8(3):405-408
We estimate the contribution of f2 trajectory exchange to the central and production. It is shown that secondary reggeons may give a large contribution to processes of double diffractive meson production
at high energies.
Received: 10 May 2000 / Accepted: 4 June 2000 相似文献
11.
M.V. Polyakov A. Sibirtsev K. Tsushima W. Cassing K. Goeke 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):115-118
The possibility for an observation of a narrow penta-quark Z+-baryon in NN reactions is discussed. It is shown that the pp↦nΣ+
K
+ reaction at excess energies around 100 MeV above threshold provides optimal conditions for Z+-baryon detection by an analysis of the nK+ invariant mass spectrum, if the Z+ mass is located around 1.5 GeV involving a rather narrow width.
Received: 24 May 2000 / Accepted: 3 August 2000 相似文献
12.
N. Boulanger F. Buisseret V. Mathieu C. Semay 《The European Physical Journal A - Hadrons and Nuclei》2008,38(3):317-330
Arguments are given that support the interpretation of the lattice QCD glueball and gluelump spectra in terms of bound states
of massless constituent gluons with helicity 1. In this scheme, we show that the mass hierarchy of the currently known gluelumps
and glueballs is mainly due to the number of constituent gluons and can be understood within a simple flux tube model. It
is also argued that the lattice QCD 0+- glueball should be seen as a four-gluon bound state. We finally predict the mass of the 0- state, not yet computed in lattice QCD. 相似文献
13.
Careful review of all the evidence makes it clear that at least three states are important at 12.4-MeV excitation in 20Ne (four, if the broad (2+) at 12.5 MeV is included). The three states are 3 - , 0 + , and 1 + (0+). The latter, which is quite strong in 19F (3He, d) singles, is probably the state observed in coincidence with 6.13-MeV γ-rays in 19F(3He, dγ).
Received: 19 August 2002 / Accepted: 28 October 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: fortune@physics.upenn.edu
Communicated by D. Guerreau 相似文献
14.
L.V. Fil'kov V.L. Kashevarov E.S. Konobeevski M.V. Mordovskoy S.I. Potashev V.A. Simonov V.M. Skorkin S.V. Zuev 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):369-374
The analysis of new experimental data, obtained at the Proton Linear Accelerator of INR, with the aim to search for supernarrow
dibaryons in the pd↦ppX
1 and pd↦pdX
2 reactions is presented. Narrow peaks with an experimental width of 5 MeV at masses of 1904±2, 1926±2, and 1942±2 MeV have
been observed in missing mass M
pX1 spectra. In the missing mass M
X1 spectra, the peaks at M
X1 = 966±2, 986±2, and 1003±2 MeV have been found. The analysis of the data obtained leads to the conclusion that the observed
peaks in M
pX1 spectra are most likely supernarrow dibaryons, the decay of which into two nucleons is forbidden by the Pauli exclusion principle.
An alternative interpretation of the spectra by assuming a decay of the supernarrow dibaryons in “exotic baryon states” with
masses M
X1 is discussed.
Received: 22 October 2001 / Accepted: 15 November 2001 相似文献
15.
S. R. Cotanch I. J. General P. Wang 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):656-661
The Coulomb gauge Hamiltonian model is used to calculate masses for selected JPC states consisting of exotic combinations of quarks and gluons: ggg glueballs (oddballs), qˉg hybrid mesons and qˉqˉ tetraquark systems. An odderon Regge trajectory is computed for the J- glueballs with intercept much smaller than the pomeron, explaining its nonobservation. The lowest 1-+ hybrid-meson mass is found to be just above 2.2GeV while the lightest tetraquark state mass with these exotic quantum numbers
is predicted around 1.4GeV consistent with the observed π(1400). 相似文献
16.
Z. Rudy W. Cassing L. Jarczyk B. Kamys P. Kulessa 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):303-314
The production of K+-mesons in proton-nucleus collisions from 1.0 to 2.5GeV is analyzed with respect to one-step nucleon-nucleon ( NN → NYK
+) and two-step Δ-nucleon ( ΔN → K
+
YN) or pion-nucleon ( πN → K
+
Y) production channels on the basis of a coupled-channel transport approach (CBUU) including the kaon final-state interactions.
The influence of momentum-dependent potentials for the nucleon, hyperon and kaon in the final state are studied as well as
the importance of K+ elastic rescattering in the target nucleus. The transport calculations are compared to the experimental K+ spectra taken at LBL Berkeley, SATURNE, CELSIUS, GSI and COSY-Jülich. It is found that the momentum-dependent baryon potentials
affect the excitation function of the K+ cross-section; at low bombarding energies of ∼ 1.0GeV the attractive baryon potentials in the final state lead to a relative
enhancement of the kaon yield, whereas the net repulsive potential at bombarding energies ∼ 2GeV causes a decrease of the
K+ cross-section. Furthermore, it is pointed out that especially the K+ spectra at low momenta (or kinetic energy T
K) allow to determine the in-medium K+ potential almost model independently due to a relative shift of the K+ spectra in kinetic energy that arises from the acceleration of the kaons when propagating out of the nuclear medium to free
space, i.e. converting the potential energy to the kinetic energy of the free kaon.
Received: 28 January 2002 / Accepted: 3 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: Wolfgang.Cassing@theo.physik.uni-giessen.de
Communicated by P. Schuck 相似文献
17.
18.
Yu.S. Surovtsev D. Krupa M. Nagy 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):409-416
In a combined analysis of the experimental data on the coupled processes ππ↦ππ, KˉK in the channel with I
G
J
PC = 0+0+ +, the various scenarios of these reactions (with different numbers of resonances) are considered. In a model-independent approach,
based only on analyticity and unitarity, a resonance is represented by a pole cluster (poles on the Riemann surface) of the
definite type that is defined by the state nature. The best scenario contains the resonances f
0(665) (with properties of the σ-meson), f
0(980) (with a dominant sˉs component), f
0(1500) (with a dominant flavour-singlet, e.g., glueball component) and the f
0(1710) (with a considerable sˉs component). If the f
0(1370) exists, it has a dominant sˉs component. The coupling constants of the observed states with the considered channels and the ππ and KˉK scattering lengths are obtained. The conclusion on the linear realization of chiral symmetry is drawn.
Received: 25 April 2002 / Accepted: 4 June 2002 / Published online: 26 November 2002
RID="a"
ID="a"e-mail: surovcev@thsun1.jinr.ru
RID="b"
ID="b"e-mail: krupa@savba.sk
RID="c"
ID="c"e-mail: fyzinami@nic.savba.sk
Communicated by V.V. Anisovich 相似文献
19.
S. Sodaye K. Sudarshan B.S. Tomar A. Goswami S. Mukherjee K. Mahata 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):371-376
Kinetic-energy spectra and angular distribution of projectile-like fragments have been measured in the reaction of 84 MeV
12C on 169Tm, using the surface barrier silicon-based ΔE-E telescopes. The fragments close to the projectile show typical spectra of quasi-elastic transfer reactions, which were found
to be in agreement with the calculations based on the direct surface transfer reaction model. A significant cross-section
of fast alpha-particles was found at forward angles, reminiscent of incomplete fusion reactions, which could be explained
in terms of the direct surface transfer reaction model after taking into account the level density of continuum states in
the heavy reaction product. The results have been explained in terms of the continuous evolution of the reaction mechanism
as a function of the mass transfer.
Received: 13 March 2002 / Accepted: 3 May 2002 相似文献
20.
Liao Hongbo 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):461-464
The production of σ and κ in J/ψ decays is presented using 58 million J/ψ events collected at BES II detector. We also report the study of the light scalar mesons f
0(980), f
0(1370), f
0(1500) and f
0(1710) etc. in J/ψ decays. 相似文献