共查询到20条相似文献,搜索用时 15 毫秒
1.
J. Bordes Chan Hong-Mo Tsou Sheung Tsun 《The European Physical Journal C - Particles and Fields》2003,27(2):189-200
It is shown that existing data on the mixing between up and down fermion states and on the hierarchical mass ratios between
fermion generations, as far as can be so analyzed at present, are all consistent with the two phenomena being both consequences
of a mass matrix rotating in generation space with changing energy scale. As a result, the rotating mass matrix can be traced
over some 14 orders of magnitude in energy from the mass scale of the t quark at 175 GeV to below that of the atmospheric neutrino at 0.05 eV.
Received: 27 August 2002 / Published online: 24 January 2003
RID="a"
ID="a" e-mail: jose.m.bordes@uv.es
RID="b"
ID="b" e-mail: h.m.chan@rl.ac.uk
RID="c"
ID="c" e-mail: tsou@maths.ox.ac.uk 相似文献
2.
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
RID="a"
ID="a" e-mail: deppisch@physik.uni-wuerzburg.de
RID="b"
ID="b" e-mail: paes@physik.uni-wuerzburg.de
RID="c"
ID="c" e-mail: asredelb@physik.uni-wuerzburg.de
RID="d"
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
3.
H. Czyz A. Grzelinska J.H. Kühn G. Rodrigo 《The European Physical Journal C - Particles and Fields》2003,27(4):563-575
The radiative return offers the unique possibility for a measurement of the cross section of electron-positron annihilation
into hadrons over a wide range of energies. The large luminosity of present - and B-factories easily compensates for the additional factor of due to the emission of a hard photon. Final states with photons at large angles can be easily identified. The rate for events
with collinear photons, however, is enhanced by a large logarithm and allows, in particular at lower energies, for a complementary
measurement. The Monte Carlo generator PHOKHARA, which includes next-to-leading order corrections from virtual and real photon
emission, has been extended from large photon angles into the collinear region, using recent results for the virtual corrections.
In addition, the present version includes final state radiation for muon and pion pair production and final states with four
pions. Implications for the experimental analysis at three typical energies, 1.02, 4 and 10.6 GeV, are presented: the magnitude
of these new corrections is studied, possibilities for the separation of initial and final state radiation are proposed, and
the differences with respect to the previous treatment based on structure functions are investigated.
Received: 16 December 2002 / Published online: 26 February 2003
RID="a"
ID="a" e-mail: czyz@us.edu.pl
RID="b"
ID="b" e-mail: grzel@joy.phys.us.edu.pl, Supported in part by "Marie Curie Training Site" at Karlsruhe University
RID="c"
ID="c" e-mail: jk@particle.uni-karlsruhe.de
RID="d"
ID="d" e-mail: german.rodrigo@cern.ch, Supported in part by E.U. TMR grant HPMF-CT-2000-00989 相似文献
4.
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
RID="c"
ID="c" e-mail: hollik@mppmu.mpg.de
RID="d"
ID="d" e-mail: slavich@mppmu.mpg.de
RID="e"
ID="e" e-mail: Georg.Weiglein@durham.ac.uk 相似文献
5.
M. Davier S. Eidelman A. Höcker Z. Zhang 《The European Physical Journal C - Particles and Fields》2003,27(4):497-521
Vacuum polarization integrals involve the vector spectral functions which can be experimentally determined from two sources:
(i) e
+
e
-
annihilation cross sections and (ii) hadronic decays. Recently results with comparable precision have become available from CMD-2 on one side, and ALEPH, CLEO and OPAL
on the other. The comparison of the respective spectral functions involves a correction from isospin-breaking effects, which
is evaluated. After the correction it is found that the dominant spectral functions do not agree within experimental and theoretical uncertainties. Some disagreement is also found for the
spectral functions. The consequences of these discrepancies for vacuum polarization calculations are presented, with the
emphasis on the muon anomalous magnetic moment. The work includes a complete re-evaluation of all exclusive cross sections,
taking into account the most recent data that became available in particular from the Novosibirsk experiments and applying
corrections for the missing radiative corrections. The values found for the lowest-order hadronic vacuum polarization contributions
are where the errors have been separated according to their sources: experimental, missing radiative corrections in e
+
e
-
data, and isospin breaking. The Standard Model predictions for the muon magnetic anomaly read where the errors account for the hadronic, light-by-light scattering and electroweak contributions. We observe deviations
with the recent BNL measurement at the 3.0 (e
+
e
-
) and 0.9 () level, when adding experimental and theoretical errors in quadrature.
Received: 27 August 2002 / Revised version: 10 January 2003 / Published online: 26 February 2003
RID="a"
ID="a" e-mail: davier@lal.in2p3.fr
RID="b"
ID="b" e-mail: simon.eidelman@cern.ch
RID="c"
ID="c" e-mail: hoecker@lal.in2p3.fr
RID="d"
ID="d" e-mail: zhangzq@lal.in2p3.fr 相似文献
6.
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
RID="b"
ID="b" e-mail: nezri@in2p3.fr
RID="c"
ID="c" e-mail: orloff@in2p3.fr 相似文献
7.
We address the problem that the cross section for the collisions of unstable particles diverges, if calculated by standard
methods. This problem is considered for beams much smaller than the decay length of the unstable particle, much larger than
the decay length and finally also for pancake- shaped beams. We find that in all cases this problem can be solved by taking
into account the production/propagation of the unstable particle and/or the width of the incoming wave packets in momentum
space.
Received: 4 March 2003 / Revised version: 8 April 2003 / Published online: 23 May 2003
RID="a"
ID="a" e-mail: chrisd@sci.kun.nl
RID="b"
ID="b" e-mail: kleiss@sci.kun.nl 相似文献
8.
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
RID="a"
ID="a"e-mail: fiore@cs.infn.it
RID="b"
ID="b"e-mail: flachi@ifae.es
RID="c"
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
9.
C. Dams R. Kleiss P. Draggiotis E.N. Argyres A. van Hameren C.G. Papadopoulos 《The European Physical Journal C - Particles and Fields》2003,28(4):561-571
We introduce a class of self-interacting scalar theories in which the various coupling constants obey a recursive relation.
These imply a particularly simple form for the generating function of the Feynman amplitudes with vanishing external momenta,
as well as for the effective potential. In addition we discuss an interesting duality inherent in these models. Specializing
to the case of zero spacetime dimensions we find intriguing nullification properties for the amplitudes.
Received: 19 December 2001 / Published online: 5 May 2003
RID="a"
ID="a" e-mail: chrisd@sci.kun.nl
RID="b"
ID="b" e-mail: kleiss@sci.kun.nl
RID="c"
ID="c" e-mail: petros@sci.kun.nl
RID="d"
ID="d" e-mail: andrevh@sci.kun.nl
RID="e"
ID="e" e-mail: papadopo@alice.nuclear.demokritos.gr 相似文献
10.
R.P. Duperray K.V. Protasov A.Yu. Voronin 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):27-34
The experimental data of the antideuteron production in proton-proton and proton-nucleus collisions are analyzed within a
simple model based on the diagrammatic approach to the coalescence model. This model is shown to be able to reproduce most
of the existing data without any additional parameter.
Received: 18 April 2002 / Accepted: 30 August 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: duperray@isn.in2p3.fr
RID="b"
ID="b"e-mail: protasov@isn.in2p3.fr
RID="c"
ID="c"e-mail: avoronin@aha.ru
Communicated by A. Molinari 相似文献
11.
N. Kan K. Sakamoto K. Shiraishi 《The European Physical Journal C - Particles and Fields》2003,28(3):425-430
We calculate the effective potential for the WLPNGB in a world with a circular latticized extra dimension. The mass of the
Wilson line pseudo-Nambu-Goldstone boson (WLPNGB) is calculated from the one-loop quantum effect of scalar fields at zero
and finite temperature. We show that a series expansion by the modified Bessel functions is useful to calculate the one-loop
effective potentials.
Received: 24 January 2003 / Published online: 14 April 2003
RID="a"
ID="a" e-mail: b1834@sty.cc.yamaguchi-u.ac.jp
RID="b"
ID="b" e-mail: b1795@sty.cc.yamaguchi-u.ac.jp
RID="c"
ID="c" e-mail: shiraish@po.cc.yamaguchi-u.ac.jp 相似文献
12.
D. Klabucar K. Kumericki D. Mekterovic B. Podobnik 《The European Physical Journal C - Particles and Fields》2003,29(1):71-78
If instantons are introduced into the MIT bag model in such a way that the bag radii are allowed to vary, the MIT bag interior
can accommodate an instanton density which is by an order of magnitude larger than in the case when the radii are fixed (although
it is still significantly smaller than in the non-perturbative QCD vacuum). The instanton contribution to the baryon mass
shifts is also correspondingly larger. The instanton-induced part of the scalar strangeness of the nucleon MIT bag is an order
of magnitude larger than found previously, within the linearized approximation. The decrease of the model radii (which is
associated with the increase of the instanton density) is very favorable from the standpoint of nuclear physics.
Received: 7 February 2003 / Revised version: 1 April 2003 / Published online: 23 May 2003
RID="a"
ID="a" e-mail: klabucar@phy.hr
RID="b"
ID="b" e-mail: kkumer@phy.hr
RID="c"
ID="c" e-mail: dmekter@rudjer.irb.hr
RID="d"
ID="d" e-mail: bp@phy.hr. Present address: Faculty of Civil Engineering, University of Rijeka, HR-51000 Rijeka, Croatia 相似文献
13.
We propose a phenomenological form of the charged lepton mass matrix which extends the idea of a ”lopsided” mass matrix found
in the literature. The features of the form are that both the 2-3 and 1-3 elements of the charged lepton mass matrix are of
order 1 and that the small elements have a new structure. This form leads to the interesting result that both large atmospheric
and solar neutrino mixing can be accounted for by the matrix. Another interesting result of this mass matrix is that it leads
to very small 1-3 mixing in the lepton sector and can suppress the branching ratio of under the present experimental limit in the supersymmetric see-saw case.
Received: 3 October 2002 / Revised version: 10 November 2002 / Published online: 24 January 2003
RID="a"
ID="a" e-mail: bixj@mail.tsinghua.edu.cn
RID="b"
ID="b" e-mail: dyb@itp.ac.cn 相似文献
14.
T.M. Aliev A. Özpineci M. Savci 《The European Physical Journal C - Particles and Fields》2003,29(2):265-270
We study the effects of sequential fourth quark generation in rare decays induced by the transition and in B
s
0- mixing. Using the experimental values on the branching ratios of the and decays, the allowed regions for and are determined as a function of the t
'
quark mass.
Received: 3 April 2003 / Published online: 2 June 2003
RID="a"
ID="a" e-mail: taliev@metu.edu.tr
RID="b"
ID="b" e-mail: ozpineci@ictp.trieste.it
RID="c"
ID="c" e-mail: savci@metu.edu.tr 相似文献
15.
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
16.
17.
18.
I. Lubashevsky P. Wagner R. Mahnke 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):243-247
This paper introduces a car following model where the driving scheme takes into account the deficiencies of human decision
making in a general way. Additionally, it improves certain shortcomings of most of the models currently in use: it is stochastic
but has a continuous acceleration. This is achieved at the cost of formulating the model in terms of the time derivative of
the acceleration, making it non-Newtonian. However, the recipe for construction of bounded rational driver models proposed
in this paper seems to be very general and can be applied to most, if not all of the traditional car-following models.
Received 18 November 2002 / Received in final form 6 February 2003 Published online 1st April 2003
RID="a"
ID="a"e-mail: ialub@fpl.gpi.ru
RID="b"
ID="b"e-mail: peter.wagner@dlr.de
RID="c"
ID="c"e-mail: reinhard.mahnke@physik.uni-rostock.de 相似文献
19.
We study the differential branching ratio, the branching ratio and the forward-backward asymmetry for exclusive decay in the two Higgs doublet model. We analyze the dependences of these quantities on the model parameters and show that
these observables are highly sensitive to new physics and hence may provide a powerful probe of the SM and beyond.
Received: 27 March 2002 / Revised version: 3 July 2002 / Published online: 20 September 2002
RID="a"
ID="a" e-mail: gurerk@newton.physics.metu.edu.tr
RID="b"
ID="b" e-mail: gsevgur@metu.edu.tr 相似文献
20.
K. Ikematsu K. Fujii Z. Hioki Y. Sumino T. Takahashi 《The European Physical Journal C - Particles and Fields》2003,29(1):1-10
We developed a new method for the full kinematical reconstruction of the system near its threshold at future linear e
+
e
-
colliders. In the core of the method lies likelihood fitting which is designed to improve measurement accuracies of the kinematical
variables that specify the final states resulting from decays. The improvement is demonstrated by applying this method to a Monte Carlo sample generated with various experimental effects including beamstrahlung, finite acceptance and resolution of the detector
system, etc. In most cases the fit takes a broad non-Gaussian distribution of a given kinematical variable to a nearly Gaussian
shape, thereby justifying phenomenological analyses based on simple Gaussian smearing of the parton-level momenta. The standard
deviations of the resultant distributions of various kinematical variables are given in order to facilitate such phenomenological
analyses. A possible application of the kinematical fitting method and its expected impact are also discussed.
Received: 4 March 2003 / Published online: 23 May 2003
RID="a"
ID="a" e-mail: ikematsu@post.kek.jp
RID="b"
ID="b" e-mail: fujiik@jlcuxf.kek.jp
RID="c"
ID="c" e-mail: hioki@ias.tokushima-u.ac.jp
RID="d"
ID="d" e-mail: sumino@tuhep.phys.tohoku.ac.jp
RID="e"
ID="e" e-mail: tohrut@hiroshima-u.ac.jp 相似文献