共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
We study the implications of the recently improved upper limits on the branching ratios for the decays , expressed as . We work out the constraints that the current bound on implies on the parameters of the quark mixing matrix in the standard model (SM). Using the present profile of the unitarity
triangle, we predict this ratio to lie in the range (at 95% C.L.), with the central value . We also work out the correlations involving , the isospin-violating ratio , and the direct CP-violating asymmetry in decays in the SM, in the minimal supersymmetric extension of the SM (MSSM), and in an extension of the MSSM involving an
additional flavor-changing structure in transitions.
Received: 19 August 2002 / Published online: 18 October 2002
RID="a"
ID="a" e-mail: ali@mail.desy.de
RID="b"
ID="b" e-mail: lunghi@mail.desy.de 相似文献
3.
R. Erdem 《The European Physical Journal C - Particles and Fields》2002,25(4):623-628
We give a simple model to explain the origin of fermion families and chirality through the use of a domain wall-anti-domain
wall pair placed in a five dimensional space-time.
Received: 14 March 2002 / Revised version: 3 July 2002 / Published online: 27 September 2002
RID="a"
ID="a" e-mail: erdem@likya.iyte.edu.tr 相似文献
4.
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
5.
6.
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
7.
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
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.
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
RID="b"
ID="b" e-mail: kumamoto@cosmos01.cla.kagoshima-u.ac.jp
RID="c"
ID="c" e-mail: minaka@edu.kagoshima-u.ac.jp
RID="d"
ID="d" e-mail: nakamura@sci.kagoshima-u.ac.jp
RID="e"
ID="e" e-mail: ohkura@cosmos01.cla.kagoshima-u.ac.jp
RID="f"
ID="f" e-mail: yamaguchi@cosmos01.cla.kagoshima-u.ac.jp 相似文献
10.
T. Dobrowolski 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):269-271
The production of topological defects during a quench in a φ4 model is investigated. The influence of a spatially correlated noise on defect production in two and three dimensions is
demonstrated.
Received 28 August 2001 / Received in final form 11 February 2002 Published online 2 October 2002
RID="a"
ID="a"Paper supported in part by ESF “COSLAB” Programme
RID="b"
ID="b"e-mail: sfdobrow@kinga.cyf-kr.edu.pl 相似文献
11.
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
12.
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
RID="b"
ID="b" e-mail: cktorid@cc.uoa.gr
RID="c"
ID="c" e-mail: stefanis@tp2.ruhr-uni-bochum.de 相似文献
13.
V.K. Henner P.G. Frick T.S. Belozerova V.G. Solovyev 《The European Physical Journal C - Particles and Fields》2002,26(1):3-7
We demonstrate the advantages of the wavelet analysis (WA) for resolving the structures in experimental data on e
+
e
-
annihilation into hadron states with quantum numbers of meson. The WA yields a useful set of starting conditions for analysis of states with multiresonance unitary Breit-Wigner method. We also apply the WA for the ratio R
e+e-
.
Received: 4 February 2002 / Revised version: 28 August 2002 / Published online: 18 October 2002
RID="a"
ID="a" e-mail: vhenner@python.physics.louisville.edu and henner@psu.ru 相似文献
14.
V.A. Petrov E. Predazzi A. Prokudin 《The European Physical Journal C - Particles and Fields》2003,28(4):525-533
An analysis of the Coulombic amplitude and its interference with the nuclear amplitude which is driven by the three-component
pomeron is presented. It is shown that different approaches towards the evaluation of the Coulomb phase give approximately
uniform results at all energies and the differences are negligible at RHIC and LHC energies. We show that the use of the amplitude
which was fitted to accommodate the nucleon data only (in the region (GeV2)), combined with the Coulomb amplitude, reproduces the existing data in the Coulomb interference domain quite accurately
without any adjustment of the parameters. As a consequence, we predict the differential cross section in the region of the
Coulomb nucleon interference for both RHIC and LHC energies.
Received: 3 June 2002 / Revised version: 27 February 2003 / Published online: 5 May 2003
RID="a"
ID="a" e-mail: petrov@mx.ihep.su
RID="b"
ID="b" e-mail: predazzi@to.infn.it
RID="c"
ID="c" e-mail: prokudin@to.infn.it 相似文献
15.
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
RID="c"
ID="c" e-mail: hshin@kias.re.kr 相似文献
16.
J.M. Grimstrup R. Wulkenhaar 《The European Physical Journal C - Particles and Fields》2002,26(1):139-151
We analyse two new versions of -expanded non-commutative quantum electrodynamics up to first order in and first loop order. In the first version we expand the bosonic sector using the Seiberg-Witten map, leaving the fermions
unexpanded. In the second version we leave both bosons and fermions unexpanded. The analysis shows that the Seiberg-Witten
map is a field redefinition at first order in . However, at higher order in the Seiberg-Witten map cannot be regarded as a field redefinition. We find that the initial action of any -expanded massless non-commutative QED must include one extra term proportional to which we identify by loop calculations.
Received: 3 July 2002 / Published online: 7 October 2002
RID="a"
ID="a" e-mail: jesper@hep.itp.tuwien.ac.at Work supported by The Danish Research Agency.
RID="b"
ID="b" e-mail: raimar.wulkenhaar@mis.mpg.de Schloe?mann fellow 相似文献
17.
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
18.
E. Martynov E. Predazzi A. Prokudin 《The European Physical Journal C - Particles and Fields》2002,26(2):271-284
A model based on a dipole pomeron framework for exclusive vector meson photoproduction by real and virtual photons shows
very good agreement with the experimental data. This model does not violate unitarity constraints and describes in a universal
manner all the available data for , , , and vector meson photoproduction in the region of energies and photon virtualities .
Received: 18 December 2001 / Published online: 25 October 2002
RID="a"
ID="a" e-mail: martynov@bitp.kiev.ua
RID="b"
ID="b" e-mail: predazzi@to.infn.it
RID="c"
ID="c" e-mail: prokudin@to.infn.it 相似文献
19.
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
20.
Recent experiments on unzipping of RNA helix-loop structures by force have shown that ≈40-base molecules can undergo kinetic
transitions between two well-defined “open” and “closed” states, on a timescale ≈1 sec [Liphardt et al., Science 297, 733-737 (2001)]. Using a simple dynamical model, we show that these phenomena result from the slow kinetics
of crossing large free energy barriers which separate the open and closed conformations. The dependence of barriers on sequence
along the helix, and on the size of the loop(s) is analyzed. Some DNA and RNA sequences that could show dynamics on different
time scales, or three(or more)-state unzipping, are proposed. Our dynamical model is also applied to the unzipping of long
(kilo-basepair) DNA molecules at constant force.
Received 29 July 2002 / Received in final form 5 February 2003 Published online: 16 April 2003
RID="a"
ID="a"e-mail: cocco@ldfc.u-strasbg.fr
RID="b"
ID="b"e-mail: jmarko@uic.edu
RID="c"
ID="c"e-mail: monasson@lpt.ens.fr 相似文献