共查询到20条相似文献,搜索用时 31 毫秒
1.
A. van Hameren C.G. Papadopoulos 《The European Physical Journal C - Particles and Fields》2002,25(4):563-574
We present a ”hierarchical” strategy for phase space generation in order to efficiently map the antenna momentum structures,
typically occurring in QCD amplitudes.
Received: 4 April 2002 / Revised version: 6 June 2002 / Published online: 20 September 2002
RID="a"
ID="a" e-mail: andrevh@inp.demokritos.gr
RID="b"
ID="b" e-mail: Costas.Papadopoulos@cern.ch 相似文献
2.
3.
Karanikas A.I. Ktorides C.N. Stefanis N.G. 《The European Physical Journal C - Particles and Fields》2003,26(3):445-455
We employ the Polyakov world-line path-integral version of QCD to identify and resum at leading perturbative order enhanced
radiative gluon contributions to the Drell-Yan type ( pair annihilation) cross-sections. We emphasize that this is the first time that world-line techniques are applied to cross-section
calculations.
Received: 10 June 2002 / Published online: 31 October 2002
RID="a"
ID="a" e-mail: akaranik@cc.uoa.gr
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ID="b" e-mail: cktorid@cc.uoa.gr
RID="c"
ID="c" e-mail: stefanis@tp2.ruhr-uni-bochum.de 相似文献
4.
V.I. Demchik V.V. Skalozub 《The European Physical Journal C - Particles and Fields》2003,26(4):601-607
The spontaneous generation of magnetic and chromomagnetic fields at high temperature in the minimal supersymmetric standard
model is investigated. The consistent effective potential including the one-loop and the daisy diagrams of all bosons and
fermions is calculated and the magnetization of the vacuum is observed. The mixing of the generated fields due to the quark
and s-quark loop diagrams and the role of superpartners are studied in detail. It is found that the contribution of these diagrams
increases the magnetic and chromomagnetic field strengths as compared with the case of a separate generation of fields. The
magnetized vacuum state is found to be stable due to the magnetic masses of gauge fields included in the daisy diagrams. Applications
of the results obtained are discussed. A comparison with the standard model case is given.
Received: 18 October 2002 / Revised version: 23 December 2002 / Published online: 3 March 2003
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ID="a" e-mail: vadimdi@yahoo.com
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ID="b" e-mail: skalozub@ff.dsu.dp.ua 相似文献
5.
We revisit the decoupling phenomenon of massless modes in non-commutative open string (NCOS) theories. We check the decoupling
by explicit computation in (2+1) or higher dimensional NCOS theories and recapitulate the validity of the decoupling to all
orders in perturbation theory.
Received: 23 April 2002 / Published online: 25 October 2002
RID="a"
ID="a" e-mail: hyun@phya.yonsei.ac.kr
RID="b"
ID="b" e-mail: sangmin@newton.skku.ac.kr
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ID="c" e-mail: hshin@kias.re.kr 相似文献
6.
7.
S. Kagiyama S. Kumamoto A. Minaka A. Nakamura K. Ohkura S. Yamaguchi 《The European Physical Journal C - Particles and Fields》2002,25(3):453-458
The phase structure of hadrons and the quark-gluon plasma is investigated by two types of equation of state of the hadrons,
namely the ideal hadron gas model and the compressible bag model. It is pointed out that, while the ideal gas model produces
an unrealistic extra hadron phase, the compressible bag model gives the expected and reasonable phase diagram even if the
rich hadron spectrum is taken into account.
Received: 22 February 2002 / Revised version: 28 June 2002 / Published online: 20 September 2002
RID="a"
ID="a" e-mail: kagiyama@sci.kagoshima-u.ac.jp
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ID="b" e-mail: kumamoto@cosmos01.cla.kagoshima-u.ac.jp
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ID="c" e-mail: minaka@edu.kagoshima-u.ac.jp
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ID="d" e-mail: nakamura@sci.kagoshima-u.ac.jp
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ID="e" e-mail: ohkura@cosmos01.cla.kagoshima-u.ac.jp
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ID="f" e-mail: yamaguchi@cosmos01.cla.kagoshima-u.ac.jp 相似文献
8.
F. Deppisch H. Päs A. Redelbach R. Rückl Y. Shimizu 《The European Physical Journal C - Particles and Fields》2003,28(3):365-374
We discuss the perspectives of testing the right-handed Majorana mass scale MR of the SUSY see-saw model in the mSUGRA framework. Lepton-flavor violating low energy processes are analyzed in recently
proposed post-LEP benchmark scenarios, taking into account present uncertainties and future developments in the neutrino sector.
Non-observation of in the next-generation PSI experiment will provide upper bounds on MR of the order of GeV, while on the other hand, a positive signal for at SUPERKEKB or the LHC may determine MR for a given mSUGRA scenario with an accuracy of a factor of 2.
Received: 14 June 2002 / Revised version: 7 January 2003 / Published online: 14 April 2003
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ID="a" e-mail: deppisch@physik.uni-wuerzburg.de
RID="b"
ID="b" e-mail: paes@physik.uni-wuerzburg.de
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ID="c" e-mail: asredelb@physik.uni-wuerzburg.de
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ID="d" e-mail: rueckl@physik.uni-wuerzburg.de
RID="e"
ID="e" e-mail: shimizu@eken.phys.nagoya-u.ac.jp 相似文献
9.
N. Singhal V. Prasad M. Mohan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):293-298
The molecular dynamics of polar diatomic molecule, interacting with linearly and circularly polarised laser field is studied.
Non-perturbative quasi-energy technique is used to determine the rotational field surfaces. Degeneracy in different M-levels
is found to be removed in the presence of circularly polarised electromagnetic radiation. In this paper, we present the calculations
exhibiting the dynamics of rotational excitation of a linear molecule and characteristic features of spectra which become
observable in considered fields.
Received 22 March 2002 / Received in final form 15 July 2002 Published online 6 November 2002
RID="a"
ID="a"e-mail: nsinghal@physics.du.ac.in
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ID="b"e-mail: vnautiyal@himalaya.du.ac.in
RID="c"
ID="c"e-mail: manmohan@physics.du.ac.in 相似文献
10.
G. Degrassi S. Heinemeyer W. Hollik P. Slavich G. Weiglein 《The European Physical Journal C - Particles and Fields》2003,28(1):133-143
The status of the evaluation of the MSSM Higgs sector is reviewed. The phenomenological impact of recently obtained corrections
is discussed. In particular it is shown that the upper bound on mh within the MSSM is shifted upwards. Consequently, lower limits on obtained by confronting the upper bound as function of with the lower bound on mh from Higgs searches are significantly weakened. Furthermore, th
e region in the MA--plane where the coupling of the lightest Higgs boson to down-type fermions is suppressed is modified. The presently not calculated
higher-order corrections to the Higgs-boson mass matrix are estimated to shift the mass of the lightest Higgs boson by up
to 3 GeV.
Received: 12 December 2002 / Published online: 3 March 2003
RID="a"
ID="a" e-mail: giuseppe.degrassi@roma3.infn.it
RID="b"
ID="b" e-mail: Sven.Heinemeyer@physik.uni-muenchen.de
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ID="c" e-mail: hollik@mppmu.mpg.de
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ID="d" e-mail: slavich@mppmu.mpg.de
RID="e"
ID="e" e-mail: Georg.Weiglein@durham.ac.uk 相似文献
11.
A. Borah S. Ghosh S. Nandy 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):221-225
The novel inelastic collision properties of two-soliton interaction for an n-component coupled higher order nonlinear Schr?dinger equation are studied. Some interesting features of three soliton interactions,
related to the integrability of the n-component coupled higher order nonlinear Schr?dinger equation are also discussed.
Received 17 April 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: abhijit@iitg.ernet.in
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ID="b"e-mail: sasanka@iitg.ernet.in
RID="c"
ID="c"e-mail: sudipta@iitg.ernet.in 相似文献
12.
V. Bertin E. Nezri J. Orloff 《The European Physical Journal C - Particles and Fields》2002,26(1):111-124
We study potential signals of neutralino dark matter indirect detection by neutrino telescopes in a wide range of CMSSM parameters.
We also compare with direct detection potential signals taking into account in both cases present and future experiment sensitivities.
Only models with neutralino annihilation into gauge bosons can satisfy cosmological constraints and current neutrino indirect
detection sensitivities. For both direct and indirect detection, only next generation experiments will be able to really test
this kind of models.
Received: 12 April 2002 / Revised version: 16 July 2002 / Published online: 18 October 2002
RID="a"
ID="a" e-mail: bertin@cppm.in2p3.fr
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ID="b" e-mail: nezri@in2p3.fr
RID="c"
ID="c" e-mail: orloff@in2p3.fr 相似文献
13.
R. Capovilla C. Chryssomalakos J. Guven 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):163-166
We examine the equilibria of a rigid loop in the plane, characterized by an energy functional quadratic in the curvature,
subject to the constraints of fixed length and fixed enclosed area. Whereas the only non self-intersecting equilibrium corresponding
to the fixed length constraint is the circle, the area constraint gives rise to distinct equilibria labeled by an integer.
These configurations exhibit self-intersections and bifurcations as the area is reduced. In addition, not only can the Euler-Lagrange
equation be integrated to provide a quadrature for the curvature but the embedding itself can be expressed as a local function
of the curvature. Perturbations connecting equilibria are shown to satisfy a first order ODE which is readily solved. Analytical
expressions for the energy as a function of the area are obtained in the limiting regimes.
Received 18 October 2001 / Received in final form 31 May 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: capo@fis.cinvestav.mx
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ID="b"e-mail: chryss@nuclecu.unam.mx
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ID="c"e-mail: jemal@nuclecu.unam.mx 相似文献
14.
15.
To reach their physical goals, future neutrino factories using muon decay aim at an overall flux precision of or better. We analytically study the QED radiative corrections to the neutrino differential distributions from muon decay.
Kinematic uncertainties due to the divergence of the muon beam are considered as well. The resulting corrections to the neutrino
flux turn out to be of order , safely below the required precision.
Received: 10 September 2002 / Revised version: 4 April 2003 / Published online: 2 June 2003
RID="a"
ID="a" e-mail: alicia@delta.ft.uam.es
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ID="b" e-mail: mena@delta.ft.uam.es 相似文献
16.
R. Fiore A. Flachi L.L. Jenkovszky A.I. Lengyel V.K. Magas 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):505-515
An explicit model realizing parton-hadron duality and fitting the data is suggested. Complex nonlinear Regge trajectories
are important ingredients of the model. The inclusion of Δ and N* trajectories should account for all resonances in the direct channel. The exotic trajectory is responsible for the smooth
background.
Received: 7 June 2002 / Accepted: 3 July 2002 / Published online: 10 December 2002
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ID="a"e-mail: fiore@cs.infn.it
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ID="b"e-mail: flachi@ifae.es
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ID="c"e-mail: jenk@gluk.org
RID="d"
ID="d"e-mail: sasha@len.uzhgorod.ua
RID="e"
ID="e"e-mail: vladimir@cfif.ist.utl.pt
Communicated by V.V. Anisovich 相似文献
17.
A.T. Suzuki E.S. Santos A.G.M. Schmidt 《The European Physical Journal C - Particles and Fields》2002,26(1):125-137
In this article we present the complete massless and massive one-loop triangle diagram results using the negative dimensional
integration method (NDIM). We consider the following cases: massless internal fields; one massive, two massive with the same
mass m and three equal masses for the virtual particles. Our results are given in terms of hypergeometric and hypergeometric-type
functions of the external momenta (and masses for the massive cases) where the propagators in the Feynman integrals are raised
to arbitrary exponents and the dimension of the space-time is D. Our approach reproduces the known results; it produces other solutions as yet unknown in the literature as well. These new
solutions occur naturally in the context of NDIM revealing a promising technique to solve Feynman integrals in quantum field
theories.
Received: 14 April 2002 / Revised version: 18 July 2002 / Published online: 7 October 2002
RID="a"
ID="a" e-mail: suzuki@ift.unesp.br
RID="b"
ID="b" e-mail: esdras@ift.unesp.br
RID="c"
ID="c" e-mail: schmidt@fisica.ufpr.br 相似文献
18.
G.H. Arakelyan A. Capella A.B. Kaidalov Yu.M. Shabelski 《The European Physical Journal C - Particles and Fields》2002,26(1):81-90
The process of baryon number transfer due to string junction propagation in rapidity space is analyzed. It has a significant
effect on the net baryon production in pp collisions at mid-rapidities and an even larger effect in the forward hemisphere in the cases of and interactions. The results of numerical calculations in the framework of the quark-gluon string model are in reasonable agreement
with the data.
Received: 14 December 2001 / Revised version: 24 April 2002 Published online: 16 October 2002
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ID="a" Permanent address: Yerewan Physics Institute, Armenia and JINR, Dubna, Russia e-mail: argev@jerewan1.yerphi.am
RID="b"
ID="b" e-mail: Alphonse.Capella@th.u-psud.fr
RID="c"
RID="d" 相似文献
19.
M. Diehl P. Kroll C. Vogt 《The European Physical Journal C - Particles and Fields》2003,26(4):567-577
We study the handbag contribution to two-photon annihilation into baryon-antibaryon pairs at large energy and momentum transfer.
We derive factorization of the process amplitude into a hard subprocess and form factors describing the soft transition, assuming that the process is dominated by configurations where the (anti)quark approximately carries the full
momentum of the (anti)baryon. The form factors represent moments of time-like generalized parton distributions, so-called
distribution amplitudes. A characteristic feature of the handbag mechanism is the absence of isospin-two components in the
final state, which in combination with flavor symmetry provides relations among the form factors for the members of the lowest-lying
baryon octet. Assuming dominance of the handbag contribution, we can describe current experimental data with form factors
of plausible size, and predict the cross sections of presently unmeasured channels.
Received: 3 July 2002 / Revised version: 7 October 2002 / Published online: 20 November 2002
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ID="a" e-mail: mdiehl@physik.rwth-aachen.de
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ID="b" e-mail: kroll@physik.uni-wuppertal.de
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ID="c" e-mail: cvogt@nordita.dk 相似文献
20.
We investigate the scope of all relevant production modes of charged Higgs bosons in the MSSM, with mass larger than the
one of the top quark, at future Linear Colliders operating in mode at the TeV energy scale. Final states with one or two bosons are considered, as produced by both tree- and loop-level interactions.
Received: 8 November 2002 / Revised version: 12 February 2003 / Published online: 13 May 2003
RID="a"
ID="a" e-mail: stefano.moretti@cern.ch
RID="b"
ID="b" e-mail: kanemu@post.kek.jp 相似文献