共查询到20条相似文献,搜索用时 62 毫秒
1.
ZONG Hong-Shi CHANG Lei HOU Feng-Yao SUN Wei-Min LIU Yu-Xin 《理论物理通讯》2005,44(3):519-524
Based on the rainbow approximation of Dyson-Schwinger equation and the assumption that the full inverse quark propagator at finite chemical potential is analytic in the neighborhood of μ = 1, it is proved that the dressed quark propagator at finite chemical potential μ can be written as G0^-1 [μ] =iγ·p↑-A(p↑-^2) +B(p↑-^2) with p↑-μ= (p↑-p4 +iμ). From the dressed quark propagator at finite chemical potential in Munczek model the bag constant of a baryon and the scalar quark condensate are evaluated. A comparison with previous results is given. 相似文献
2.
J. Ellis F. Moortgat G. Moortgat-Pick J. M. Smillie J. Tattersall 《The European Physical Journal C - Particles and Fields》2009,60(4):633-651
We study the potential observation at the LHC of CP-violating effects in stop production and subsequent cascade decays,
,
,
, within the Minimal Supersymmetric Standard Model. We study T-odd asymmetries based on triple products between the different
decay products. There may be a large CP asymmetry at the parton level, but there is a significant dilution at the hadronic
level after integrating over the parton distribution functions. Consequently, even for scenarios where large CP intrinsic
asymmetries are expected, the measurable asymmetry is rather small. High luminosity and precise measurements of masses, branching
ratios and CP asymmetries may enable measurements of the CP-violating parameters in cascade decays at the LHC. 相似文献
3.
D. J. Broadhurst N. Gray K. Schilcher 《Zeitschrift fur Physik C Particles and Fields》1991,52(1):111-122
We calculate theon-shell fermion wave-function renormalization constantZ
2 of a general gauge theory, to two loops, inD dimensions and in an arbitrary covariant gauge, and find it to be gauge-invariant. In QED this is consistent with the dimensionally regularized version of the Johnson-Zumino relation: d logZ
2/da
0=i(2)–D
e
0
2
d
D
k/k
4=0. In QCD it is, we believe, a new result, strongly suggestive of the cancellation of the gauge-dependent parts of non-abelian UV and IR anomalous dimensions to all orders. At the two-loop level, we find that the anomalous dimension
F
of the fermion field in minimally subtracted QCD, withN
L light-quark flavours, differs from the corresponding anomalous dimension
of the effective field theory of a static quark by the gauge-invariant amount
相似文献
4.
In Minkowski space ${ \mathcal M }$, we derive the effective Schrödinger equation describing a spin-less particle confined to a rotating curved surface ${ \mathcal S }$. Using the thin-layer quantization formalism to constrain the particle on ${ \mathcal S }$, we obtain the relativity-corrected geometric potential ${V}_{g}^{{\prime} }$, and a novel effective potential ${\tilde{V}}_{g}$ related to both the Gaussian curvature and the geodesic curvature of the rotating surface. The Coriolis effect and the centrifugal potential also appear in the equation. Subsequently, we apply the surface Schrödinger equation to a rotating cylinder, sphere and torus surfaces, in which we find that the interplays between the rotation and surface geometry can contribute to the energy spectrum based on the potentials they offer. 相似文献
5.
WANG Jing SHI Yuan-Mei HOU Feng-Yao SUN Wei-Min ZONG Hong-Shi PING Jia-Lun 《理论物理通讯》2008,49(4):1001-1003
We do a numerical calculation on the quark-loop effects on the dressed gluon propagator in the chiral limit. It is found that the quark-loop effects on the dressed gluon propagator are significant in solving the quark propagator in the rainbow approximation of the Dyson-Schwinger equation. The approach we used here is quite general and can also be used to calculate both the chemical potential and current quark mass dependence of the dressed gluon propagator. 相似文献
6.
In the minimal supersymmetric standard model (MSSM), we study the light Higgs boson radiation off a light-chargino pair in the process
at linear colliders with
GeV. We analyze cross sections in the regions of the MSSM parameter space where the process
cannot proceed via on-shell production and subsequent decay of either heavier charginos or the pseudoscalar Higgs boson A. Cross sections up to a few fb are allowed, according to present experimental limits on the Higgs boson, chargino and sneutrino masses. We also show how a measurement of the
production rate could provide a determination of the Higgs boson couplings to charginos.Received: 24 June 2004, Revised: 13 May 2005, Published online: 19 July 2005 相似文献
7.
ZHANG Yun-Qiang LI Zhen FENG Hong-Tao 《理论物理通讯》2007,47(3):525-528
Using the coupled Dyson-Schwinger equation for the fermion propagator at finite chemical potential μ, we investigate the fermion chiral condensate when the gauge boson mass is nonzero in QED3. We show that the chiral symmetry restores when the boson mass is large enough, and the critical boson mass depends little on μ. 相似文献
8.
Dynamical chiral symmetry breaking (DCSB) in thermal QED3 with fermion velocity is studied in the framework of Dyson-Schwinger equations. By adopting instantaneous approximation and neglecting the transverse component of gauge boson propagator at finite temperature, we numerically solve the fermion self-energy equation in the rainbow approximation. It is found that both DCSB and fermion chiral condensate are suppressed by fermion velocity. Moreover, the critical temperature decreases as fermion velocity increases. 相似文献
9.
Based on the rainbow-ladder approximation of the Dyson-Schwinger equations and the assumption of the analyticity of the fermion-boson
vertex in the neighborhood of zero chemical potential (μ=0)
and neglecting the μ-dependence of the dressed gluon propagator,
we apply the method in [Phys. Rev. C 71 (2005) 015205] of studying
the dressed quark propagator at finite chemical potential to prove that the general fermion-boson vertex
at finite μ can also be obtained from the one at μ=0 by a simple shift of variables. Using this result
we extend the results of [Phys. Lett. B 420 (1998) 267] to the situation of finite chemical potential and show that under the approximations
we have taken, the Gell-Mann-Oakes-Renner relation also
holds at finite chemical potential. 相似文献
10.
In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of
11.
A Monte-Carlo analysis on production and decay of supersymmetric charginos at a future photon-collider is presented. A photon collider offers the possibility of a direct branching-ratio measurement. In this study, the process
has been considered for a specific mSUGRA scenario. Various backgrounds and a parameterised detector simulation have been included. Depending on the centre-of-mass energy, a statistical error for the directly measurable branching ratio BR(
) of up to 3.5% can be reached.Received: 14 March 2005, Revised: 31 May 2005, Published online: 28 June 2005G. Klämke: Now at: Institut für Theoretische Physik, Universität Karlsruhe, Wolfgang-Gaede-Str. 1, 76131 Karlsruhe, Germany 相似文献
12.
By making use of the φ-mapping topological current theory, this paper shows that the Gauss-Bonnet-Chern density (the Euler-Poincaré characteristic χ(M) density) can be expressed in terms of a smooth vector field φ and take the form of δ(φ), which means that only the zeros of φ contribute to χ(M). This is the elementary fact of the Hopf theorem. Furthermore, it presents that a new topological tensor current of -branes can be derived from the Gauss-Bonnet-Chern density. Using this topological current, it obtains the generalized Nambu action for multi -branes. 相似文献
13.
Using the different level of methods B3P86, BLYP, B3PW91, HF, QCISD、 CASSCF (4,4) and MP2 with the various basis functions 6-311G^**, D95, cc-pVTZ and DGDZVP, the calculations of this paper confirm that the ground state is X^-3B1 with C2v group for CH2. Furthermore, the three kinds of theoretical methods, i.e. B3P86、 CCSD(T, MP4) and G2 with the same basis set cc-pVTZ only are used to recalculate the zero-point energy revision which are modified by scaling factor 0.989 for the high level based on the virial theorem, and also with the correction for basis set superposition error. These results are also contrary to X^-3∑^-g for the ground state of CH2 in reference. Based on the atomic and molecular reaction statics, this paper proves that the decomposition type (1) i.e. CH4 →CH2+H2, is forbidden and the decomposition type (2) i.e. CH4→CHa+H is allowed for CH4. This is similar to the decomposition of SiH4. 相似文献
14.
Exact solution and exotic coherent solition structures of the (2+1)—dimensional generalized nonlinear Schroedinger equation 下载免费PDF全文
In this paper,a variable separation approach is used to obtain localized coherent structures of the (2 1)-dimensional generalized nonlinear Schroedinger equation:Iφt-(α-β)φxx (α β)φyy-2λφ[(α β)(∫-∞^x|φ|y^2ydx u1(y,t))-(α-β)(∫-∞^y|φ|x^2dy u2(x,t))]=0,By applying a special Baecklund transformation and introducing arbitrary functions of the seed solutions,the abundance of the localized structures of this model are derived.By selecting the arbitrary function appropriately,some special types of localized excitations such as dromions,dromion lattice,breathers and istantons are constructed. 相似文献
15.
Electron tunnelling phase time and dwell time through an associated delta potential barrier 下载免费PDF全文
The electron tunnelling phase time τP and dwell time τD through an associated delta potential barrier U(x) = ξδ(x) are calculated and both are in the order of 10^-17~10^-16s. The results show that the dependence of the phase time on the delta barrier parameter ξ can be described by the characteristic length lc = h^2/meξ and the characteristic energy Ec=meξ^2/h^2 of the delta barrier, where me is the electron mass, lc and Ec are assumed to be the effective width and height of the delta barrier with lcEc=ξ, respectively. It is found that TD reaches its maximum and τD = τp as the energy of the tunnelling electron is equal to Ec/2, i.e. as lc =λDB, λDB is de Broglie wave length of the electron. 相似文献
16.
Searching for the top squark(stop)is a key task to test the naturalness of SUSY.Different from stop pair production,single stop production relies on its electroweak properties and can provide some unique signatures.Following the single production process pp→t~1X(~)1→tX~10X~1-,the top quark has two decay channels:leptonic channel and hadronic channel.In this paper,we probe the observability of these two channels in a simplified minimal supersymmetric standard model scenario.We find that,at the 27 TeV LHC with the integrated luminosity of L=15 ab-1,mt-1<1900 GeV andμ<750 GeV can be excluded at 2σthrough the leptonic mono-top channel,while mt-1<1200 GeV andμ<350 GeV can be excluded at 2σthrough the hadronic channel. 相似文献
17.
Based on an extensive study of the Dyson-Schwinger equations for a fully
dressed quark propagator in the “rainbow” approximation, a parametrized form of the
quark propagator is suggested. The corresponding quark self-energy
Σf and the
structure of non-local quark vacuum condensate <0|:\bar{q}(x)q(0):|0>
are investigated. The algebraic form of the quark propagator proposed in this work describes a confining quark propagation, and is quite convenient
to be used in any numerical calculations. 相似文献
18.
Bernard Helffer 《Communications in Mathematical Physics》1994,161(3):631-643
The aim of this paper is to prove that ifV is a strictly convex potential with quadratic behavior at ∞, then the quotient μ2/μ1 between the largest eigenvalue and the second eigenvalue of the Kac operator defined on L2(? m ) by exp ?V(x)/2 · exp Δx · exp ?V(x)/2 where Δx is the Laplacian on ? m satisfies the condition: $${{\mu _2 } \mathord{\left/ {\vphantom {{\mu _2 } {\mu _1 {{ \leqslant \exp - \cosh ^{ - 1} (\sigma + 1)} \mathord{\left/ {\vphantom {{ \leqslant \exp - \cosh ^{ - 1} (\sigma + 1)} {2,}}} \right. \kern-\nulldelimiterspace} {2,}}}}} \right. \kern-\nulldelimiterspace} {\mu _1 {{ \leqslant \exp - \cosh ^{ - 1} (\sigma + 1)} \mathord{\left/ {\vphantom {{ \leqslant \exp - \cosh ^{ - 1} (\sigma + 1)} {2,}}} \right. \kern-\nulldelimiterspace} {2,}}}}$$ where σ is such that HessV(x)≥σ>0. 相似文献
19.
M. E. X. Guimarães R. M. Luna T. O. Rosa 《The European Physical Journal C - Particles and Fields》2014,74(5):1-6
We study radiative corrections to massless quantum electrodynamics modified by two dimension-five LV interactions $\bar{\Psi } \gamma ^{\mu } b'^{\nu } F_{\mu \nu }\Psi $ and $\bar{\Psi }\gamma ^{\mu }b^{\nu } \tilde{F}_{\mu \nu } \Psi $ in the framework of effective field theories. All divergent one-particle-irreducible Feynman diagrams are calculated at one-loop order and several related issues are discussed. It is found that massless quantum electrodynamics modified by the interaction $\bar{\Psi } \gamma ^{\mu } b'^{\nu } F_{\mu \nu }\Psi $ alone is one-loop renormalizable and the result can be understood on the grounds of symmetry. In this context the one-loop Lorentz-violating beta function is derived and the corresponding running coefficients are obtained. 相似文献
20.
V. V. Ammosov A. G. Denisov G. S. Gapienko V. A. Gapienko V. I. Klyukhin V. I. Koreshev P. V. Pitukhin V. I. Sirotenko Z. U. Usubov V. G. Zaetz A. E. Asratyan A. V. Fedotov P. A. Goritchev S. P. Krutchinin M. A. Kubantsev I. V. Makhlueva V. I. Shekelyan V. G. Shevchenko A. B. Krebs 《Zeitschrift fur Physik C Particles and Fields》1987,36(3):377-381
The cross section of the quasi-elastic reactions \(\bar v_\mu p \to \mu ^ + \Lambda (\Sigma ^0 )\) in the energy range 5–100 GeV is determined from Fermilab 15′ bubble chamber antineutrino data. TheQ 2 analysis of quasi-elastic Λ events yieldsM A=1.0±0.3 GeV/c2 for the axial mass value. With zero µΛ K 0 events observed, the 90% confidence level upper limit \(\sigma (\bar v_\mu p \to \mu ^ + \Lambda {\rm K}^0 )< 2.0 \cdot 10^{ - 40} cm^2 \) is obtained. At the same time, we found that the cross section of reaction \(\bar v_\mu p \to \mu ^ + \Lambda {\rm K}^0 + m\pi ^0 \) is equal to \(\left( {3.9\begin{array}{*{20}c} { + 1.6} \\ { - 1.3} \\ \end{array} } \right) \cdot 10^{ - 40} cm^2 \) . 相似文献
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