共查询到20条相似文献,搜索用时 250 毫秒
1.
The two-body decay rate of a weakly decaying particle (such as the kaon) is shown to be proportional to the square of a well-defined
transition matrix element in finite volume. Contrary to the physical amplitude, the latter can be extracted from finite-volume
correlation functions in euclidean space without analytic continuation. The K→ππ transitions and other non-leptonic decays thus become accessible to established numerical techniques in lattice QCD.
Received: 29 March 2000 / Accepted: 10 April 2000 相似文献
2.
G. Puddu 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):171-181
We extend the recently presented formalism for Monte Carlo calculations of the partition function, for both even and odd particle
number systems (Phys. Rev. C 59, 2500 (1999)), to the calculation of many-body matrix elements of the type <ψ| e
- βℋ|ψ> where |ψ> is a many-body state with a definite angular momentum, parity, neutron and proton numbers. For large β such
matrix elements are dominated by the lowest eigenstate of the many-body Hamiltonian ℋ, corresponding with a given angular
momentum parity and particle number. Emphasis is placed on odd-mass nuclei. Negligible sign fluctuations in the Monte Carlo
calculation are found provided the neutron and proton chemical potentials are properly adjusted. The formalism is applied
to the J
π = 0+ state in 166
Er and to the J
π = 9/2-, 13/2+, 5/2- states in 165
Er using the pairing-plus-quadrupole model.
Received: 28 April 2000 / Accepted: 20 September 2000 相似文献
3.
Xiang Liu 《The European Physical Journal C - Particles and Fields》2008,54(3):471-474
Very recently a new enhancement around 4.05 GeV was observed by the Belle experiment. We discuss some possible assignments
for this enhancement, i.e. the ψ(3S) and D*D̄* molecular states. In these two assignments, Y(4008) can decay into J/ψπ0π0 with a branching ratio comparable with that of Y(4008)→J/ψπ+π-. Thus, one suggests high energy experimentalists to look for Y(4008) in J/ψπ0π0 channel. Furthermore one proposes further experiments to search for the missing channels DD̄, DD̄*+h.c. and especially χcJπ+π-π0 and ηcπ+π-π0, which will be helpful to distinguish the ψ(3S) and D*D̄* molecular state assignments for this new enhancement.
PACS 13.30.Eg 13.75.Lb 相似文献
4.
Xiao-Gang He Xue-Qian Li Xiang Liu Jian-Ping Ma 《The European Physical Journal C - Particles and Fields》2007,49(3):731-736
Recently the BES collaboration has announced the observation of a resonant state in the π+π-η’ spectrum in J/ψ→γπ+π-η’ decay. Fitting the data with a 0-+ state, the mass is determined to be 1833.7 MeV with 7.7σ statistic significance. This state is consistent with the one extracted
from previously reported pp̄ threshold enhancement data in J/ψ→γpp̄. We study the properties of this state using QCD anomaly
and QCD sum rules, assuming X(1835) to be a pseudoscalar, and we show that it is consistent with the data. We find that this
state has a sizeable matrix element , leading to branching ratios of (2.61–7.37)×10-3 and (2.21–10.61)×10-2 for J/ψ→γGp and for Gp→π+π-η′, respectively. Combining the calculated branching ratio of J/ψ→γGp and data on threshold enhancement in J/ψ→γpp̄, we determine the coupling for the Gp–p–p̄ interaction. We finally study the branching ratios of the other J/ψ→γ+three mesons decay modes. We find that J/ψ→γGp→γ(π+π-η,KKπ0) can provide useful tests for the mechanism proposed.
PACS 11.55.Hx; 12.39.Fe; 12.39.Mk; 13.25.Gv 相似文献
5.
We consider a classical Coulomb gas with a short distance cutoff in two dimensions; equivalently a Sine-Gordon field theory.
For low temperature β-1 and low activityz the gas is in a multipole phase, the Kosterlitz-Thouless phase. For β>8π andz sufficiently small we give a complete renormalization group analysis for this phase and show that the flow of the effective
measures is toward a free field (infrared asymptotic freedom). This should lead to control over the long distance behavior
of the theory.
Research supported by the Natural Sciences and Engineering Research Council 相似文献
6.
7.
We find that the optical wavelet transformation can be used to study the Husimi distribution function in phase space theory
of quantum optics. We prove that the Husimi distribution function of a quantum state |ψ〉 is just the modulus square of the wavelet transform of
with ψ(x) being the mother wavelet up to a Gaussian function. Thus a convenient approach for calculating various Husimi distribution
functions of miscellaneous quantum states is presented. 相似文献
8.
It is pointed out that the coupling characterizing theψ-γ vertex must change substantially between the limits,ψ on mass-shell which occurs inψ→e
+
e
− and photon on mass-shell which is relevant in radiative decays likeψ→ππγ, ψ→ηγ and photoproduction ofψ. This has the consequence that the value ofψN total cross section must be larger than what is inferred from the use of naive vector dominance in photoproduction. 相似文献
9.
Sayipjamal Dulat Bing-Song Zou 《The European Physical Journal A - Hadrons and Nuclei》2005,26(1):125-134
With accumulation of high statistics data at BES and CLEO-c, many new interesting channels can get enough statistics for partial-wave
analysis (PWA). Among them, ψ↦γpˉ,γΛˉ,γΣˉ,γΞˉ channels provide a good place for studying baryon-antibaryon interactions; the double radiative decays ψ↦γγV with V ≡ ρ,ω,φ have a potential to provide information on the flavor content of any meson resonances (R) with positive charge parity
(C = +) and mass above 1 GeV through ψ↦γR↦γγV; ψ(2s)↦γχc0,1,2 with χc0,1,2↦Kˉπ+π- and 2π+2π- decays are good processes to study χcJ charmonium decays. Using the covariant tensor formalism, here we provide theoretical PWA formulae for these channels. 相似文献
10.
11.
L. Šamaj 《Journal of statistical physics》2006,124(5):1179-1206
This paper is a continuation of a previous one [L. Šamaj, J. Stat. Phys.
120:125 (2005)] dealing with the renormalization of a guest charge immersed in a two-dimensional logarithmic Coulomb gas of pointlike ± unit charges, the latter system being in the stability-against-collapse regime of reduced inverse temperatures 0 ≤ β < 2. In the previous work, using a sine-Gordon representation of the Coulomb gas, an exact renormalized-charge formula was derived for the special case of the pointlike guest charge Q, in its stability regime β |Q| < 2. In the present paper, we extend the renormalized-charge treatment to the guest charge with a hard core of radius σ, which allows us to go beyond the stability border β|Q| = 2. In the limit of the hard-core radius much smaller than the correlation length of the Coulomb-gas species and at a strictly finite temperature, due to the counterion condensation in the extended region β|Q| > 2, the renormalized charge Q
ren turns out to be a periodic function of the bare charge Q with period 1. The renormalized charge therefore does not saturate at a specific finite value as |Q| →∞, but oscillates between two extreme values. In the high-temperature Poisson-Boltzmann scaling regime of limits β→ 0 and Q→∞ with the product β Q being finite, one reproduces the Manning-Oosawa type of counterion condensation with the uniform saturation of β Q
ren at the value 4/π in the region β|Q| ≥ 2. The obtained results disprove the “regularization hypothesis” of the previous work about the possibility of an analytic continuation of the formula for Q
ren from the stability region β |Q| < 2 to β |Q| ≥ 2. 相似文献
12.
In this paper we give a complete characterization of Morita equivalent star products on symplectic manifolds in terms of
their characteristic classes: two star products ⋆ and ⋆' on (M,ω) are Morita equivalent if and only if there exists a symplectomorphism ψ\colon M
M such that the relative class t(⋆, ψ⋆(⋆')) is 2 π i-integral. For star products on cotangent bundles, we show that this integrality condition is related to Dirac's
quantization condition for magnetic charges.
Received: 19 July 2001 / Accepted: 23 January 2002 相似文献
13.
The Gromov–Witten invariants of a smooth, projective variety V, when twisted by the tautological classes on the moduli space of stable maps, give rise to a family of cohomological field
theories and endow the base of the family with coordinates. We prove that the potential functions associated to the tautological
ψ classes (the large phase space) and the κ classes are related by a change of coordinates which generalizes a change of basis
on the ring of symmetric functions. Our result is a generalization of the work of Manin–Zograf who studied the case where
V is a point. We utilize this change of variables to derive the topological recursion relations associated to the κ classes
from those associated to the ψ classes.
Received: 2 August 1999 / Accepted: 30 September 2000 相似文献
14.
Vladimir V. Veremey Yury A. Tuchkin 《International Journal of Infrared and Millimeter Waves》1997,18(4):909-938
An analysis of resonances of scattering from multi-element grating formed by a finite number of resonant elements is presented.
It has been shown that gratings with three and more elements on its period can support the π-mode. The π-mode of a grating
is characterized by the existence of the regions in the vicinity of the grating and along its period where the electromagnetic
field has opposite phases. The existence and excitation of the π-mode in finite gratings with resonant cells formed by several
scatterers having open cavities have been studied. The particular case of the grating with cells formed by three identical
slotted cylinders has been considered in detail. An application of gratings which support the π-mode in electron-vacuum oscillators
of millimeter waves for efficient deceleration of electrons and extracting energy from electron beam is discussed. 相似文献
15.
We analyze the extraction of weak phases from CP-violation in B → π+π- decays. We propose to determine the unitarity triangle
by combining the information on mixing-induced CP-violation in B → π+π-, S, with the precision observable sin2β obtained from the CP-asymmetry in B → ψKS. It is then possible to write down exact analytical expressions for
and
as simple functions of the observables S and sin2β and of the penguin parameters r and ϕ. As an application clean lower bounds on
and
can be derived as functions of S and sin2β, essentially without hadronic uncertainty. Computing r and ϕ within QCD factorization yields precise determinations of
and
since the dependence on r and ϕ is rather weak. It is emphasized that the sensitivity to the phase ϕ enters only at second order and is extremely small
for moderate values of this phase, predicted in the heavy-quark limit. Transparent analytical formulas are further given and
discussed for the parameter C of direct CP-violation in B → π+π-. Predictions and uncertainties for r and ϕ in QCD factorization are examined in detail. It is pointed out that a simultaneous expansion in 1/mb and 1/N leads to interesting simplifications. At first order infrared divergences are absent, while the most important effects are
retained. Independent experimental tests of the factorization framework are briefly discussed.
Received: 16 April 2005, Revised: 6 August 2005, Published online: 21 November 2005
PACS:
11.30.Er, 12.15.Hh, 13.25.Hw 相似文献
16.
Satoshi Ikeda 《International Journal of Theoretical Physics》1976,15(5):377-387
In this paper, continued from the last paper (Ikeda, 1974), two kinds of structurological generalizations of our nonlocal
field (i.e., the (x, ψ) field) are considered physicogeometrically. One is a Finslerian generalization, where the base field [i.e., the (x) field] is extended to a Finslerian field and Weyl's gauge field (i.e., the electromagnetic potential) is physically identified
with the directional vector adopted as the internal variable in the ordinary nonlocal field theory. Another is a generalization
by which the spinor (ψ) itself is taken as an independent variable, where some inherent characteristics ofψ are fused into the spatial structure. The latter is regarded as a “nonlocalization” of the (x) field accomplished by attachingψ to each point, in the true sense of the word. Particularly, the spatial structures of these generalized nonlocal fields are
described in detail. 相似文献
17.
A. K. Kwaśniewski 《Czechoslovak Journal of Physics》2001,51(12):1368-1373
It is known that one can formulateq-extended finite operator calculus with help of “quantumq-plane”q-commuting variablesA, B : AB − qBA ≡ [A, B]q=0.
We shall recall this simple fact in its natural entourage which is the so-calledψ(q)-extension of Rota’s finite operator calculus. We aim to convince the audience that this is a natural and elementary method
for formulation and treatment ofq-extended and possiblyR-extended orψ(q)-extended models for quantum-likeψ(q)-deformed oscillators.
Presented at the 10th International Colloquium on Quantum Groups: “Quantum Groups and Integrable Systems”, Prague, 21–23 June
2001. 相似文献
18.
Miroslav Engliš 《Communications in Mathematical Physics》2002,227(2):211-241
Let Ω be a bounded pseudoconvex domain in C
N
, φ, ψ two positive functions on Ω such that − log ψ, − log φ are plurisubharmonic, and z∈Ω a point at which − log φ is smooth and strictly plurisubharmonic. We show that as k→∞, the Bergman kernels with respect to the weights φ
k
ψ have an asymptotic expansion
for x,y near z, where φ(x,y) is an almost-analytic extension of &\phi;(x)=φ(x,x) and similarly for ψ. Further, . If in addition Ω is of finite type, φ,ψ behave reasonably at the boundary, and − log φ, − log ψ are strictly plurisubharmonic
on Ω, we obtain also an analogous asymptotic expansion for the Berezin transform and give applications to the Berezin quantization.
Finally, for Ω smoothly bounded and strictly pseudoconvex and φ a smooth strictly plurisubharmonic defining function for Ω,
we also obtain results on the Berezin–Toeplitz quantization.
Received: 29 December 2000 / Accepted: 14 December 2001 相似文献
19.
20.
In this article, we study the decays ψ′ → J/ψπ
+
π
− and η′c → η
c
π
+
π
− by taking into account the chiral symmetry breaking effects, the final-state interactions and the heavy-quark symmetry. We
can confront the predictions of the η′c → η
c
π
+
π
− decay width and differential decay width with the experimental data in the future, and obtain powerful constraints on the
chiral breaking effects and the final-state interactions, and test the heavy-quark symmetry. 相似文献