共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
H. Belich O.M. Del Cima M.M. Ferreira Jr. J.A. Helayël-Neto 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):145-155
We start from a parity-breaking MCS QED3 model with spontaneous breaking of the gauge symmetry as a framework for evaluation of the electron-electron interaction
potential and for attainment of numerical values for the e
-
e
-
- bound state. Three expressions ( V
eff
, V
eff
, V
eff
) are obtained according to the polarization state of the scattered electrons. In an energy scale compatible with condensed
matter electronic excitations, these three potentials become degenerated. The resulting potential is implemented in the Schr?dinger
equation and the variational method is applied to carry out the electronic binding energy. The resulting binding energies
in the scale of 10-100 meV and a correlation length in the scale of 10-30 ? are possible indications that the MCS-QED3 model adopted may be suitable to address an eventual case of e
-
e
-
pairing in the presence of parity-symmetry breakdown. The data analyzed here suggest an energy scale of 10-100 meV to fix the breaking of the U
(1)-symmetry.
Received 24 September 2002 / Received in final form 15 January 2003 Published online 1st April 2003
RID="a"
ID="a"e-mail: belich@cbpf.br
RID="b"
ID="b"e-mail: delcima@cbpf.br
RID="c"
ID="c"e-mail: manojr@cbpf.br
RID="d"
ID="d"e-mail: helayel@cbpf.br 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.
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
RID="b"
ID="b" e-mail: mena@delta.ft.uam.es 相似文献
5.
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
6.
S. Groote J.G. Körner A.A. Pivovarov 《The European Physical Journal C - Particles and Fields》2002,24(3):393-405
We propose a simple parameterization of the two-point correlator of hadronic electromagnetic currents for the evaluation
of the hadronic contributions to the muon anomalous magnetic moment. The parameterization is explicitly done in the Euclidean
domain. The model function contains a phenomenological parameter which provides an infrared cutoff to guarantee the smooth
behavior of the correlator at the origin in accordance with experimental data in e
+e- annihilation. After fixing a numerical value for this parameter from the leading order hadronic contribution to the muon
anomalous magnetic moment, the next-to-leading order results related to the vacuum polarization function are accurately reproduced.
The properties of the four-point correlator of hadronic electromagnetic currents as for instance the so-called light-by-light
scattering amplitude relevant for the calculation of the muon anomalous magnetic moment are briefly discussed.
Received: 14 December 2001 / Published online: 7 June 2002 相似文献
7.
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
8.
9.
Charmonium sum rules are analyzed with the primary goal to obtain the restrictions on the value of the dimension 4 gluon
condensate. The moments M
n
(Q
2
) of the polarization operator of the vector charm currents are calculated and compared with the experimental data. The three-loop
() perturbative corrections, the contribution of the gluon condensate with corrections and the contribution of the dimension 6 operator G3 are accounted. It is shown that the sum rules for the moments do not work at Q
2
= 0, where the perturbation series diverges and the G3 contribution is large. The domain in the (n, Q
2
) plane where the sum rules are legitimate is found. A strong correlation of the values of gluon condensate and charm quark mass is determined. The absolute limits are found to be for the gluon condensate and for the charm quark mass in the scheme.
Received: 16 July 2002 / Revised version: 6 November 2002 / Published online: 24 January 2003
RID="a"
ID="a" e-mail: ioffe@vitep1.itep.ru
RID="b"
ID="b" e-mail: zyablyuk@heron.itep.ru 相似文献
10.
J.V. Jovanović S.B. Vrhovac Z.Lj. Petrović 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):335-342
Transport properties of ion swarms in presence of Resonant Charge Transfer (RCT) collisions are studied using Momentum Transfer
Theory (MTT). It was shown that, not surprisingly, RCT collisions may be represented as a special case of elastic scattering.
Using the developed MTT we tested a previously available anisotropic set of cross-sections for Ar+Ar
+ collisions by making the comparisons with the available data for the transverse diffusion coefficient. We also developed
an anisotropic set of Ne+Ne
+ integral cross-sections based on the available data for mobility, longitudinal and transverse diffusion. Anisotropic sets
of cross-sections are needed for Monte Carlo simulations of ion transport and plasma models.
Received 16 June 2002 / Received in final form 2nd August 2002 Published online 24 September 2002
RID="a"
ID="a"e-mail: vrhovac@phy.bg.ac.yu
RID="b"
ID="b"e-mail: zoran@phy.bg.ac.yu 相似文献
11.
A. Hürstel M. Rejmund E. Bouchez P.T. Greenlees K. Hauschild S. Juutinen H. Kettunen W. Korten Y. Le Coz P. Nieminen Ch. Theisen A.N. Andreyev F. Becker T. Enqvist P.M. Jones R. Julin H. Kankaanpää A. Keenan P. Kuusiniemi M. Leino A.-P. Leppänen M. Muikku J. Pakarinen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):329-334
Prompt and delayed gamma-ray spectroscopy of very neutron-deficient bismuth isotopes 187, 189Bi has been performed using the Recoil Decay Tagging (RTD) method. The isomeric i
13/2 states have been identified and their lifetimes have been measured. The systematics of these long-lived M2 isomers has been extended to the proton-unbound isotopes. The general behaviour of single-proton states is discussed within
the systematics and interpreted within the shell-model framework.
Received: 2 May 2002 / Accepted: 3 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: wkorten@cea.fr
RID="b"
ID="b"Present address: GANIL, Caen, France.
RID="c"
ID="c"Present address: Radiation and Nuclear Safety Authority, P.O. Box 14, FIN-00881 Helsinki.
Communicated by D. Schwalm 相似文献
12.
A new evaluation of the hadronic vacuum polarization contribution to the muon magnetic moment is presented. We take into account the reanalysis of the low-energy e
+
e
-annihilation cross section into hadrons by the CMD-2 Collaboration. The agreement between e
+
e
-and
spectral functions in the
channel is found to be much improved. Nevertheless, significant discrepancies remain in the center-of-mass energy range between 0.85 and
, so that we refrain from averaging the two data sets. 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 corresponding Standard Model predictions for the muon magnetic anomaly read
where the errors account for the hadronic, light-by-light (LBL) scattering and electroweak contributions. The deviations from the measurement at BNL are found to be
(1.9
) and
(0.7
) for the e
+
e
-- and
-based estimates, respectively, where the second error is from the LBL contribution and the third one from the BNL measurement.Received: 7 September 2003, Published online: 30 October 2003 相似文献
13.
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
RID="a"
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
14.
D. Vrel S. Dubois E.M. Heian N. Karnatak M.-F. Beaufort 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):31-39
A simple method to calculate thermal diffusivity in situ after a combustion synthesis reaction is presented. The combustion reaction was analyzed via time-resolved X-ray diffraction analysis and infrared thermography. Thermal diffusivity was estimated and used to calculate
temperature profiles based on temperature profiles one second earlier. For a sample of TiC formed from Ti and C, a value of
2.00×10-6±0.20×10-6 m2 s-1 was calculated for temperatures between 1000 and 1900 K. This method is rapid and can avoid some problems associated with
furnace-based measurements of thermal diffusivity, such as recrystallization and destruction of non-equilibrium phases.
Received 29 November 2002 / Received in final form 19 March 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: vrel@limhp.univ-paris13.fr
RID="b"
ID="b"UPR 1311
RID="c"
ID="c"UMR 6630 相似文献
15.
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
16.
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
17.
M. Lach J. Styczeń W. Meczyński P. Bednarczyk A. Bracco J. Grebosz A. Maj J.C. Merdinger N. Schulz M.B. Smith K.M. Spohr J.P. Vivien M. Ziebliński 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):309-311
High-spin states of the 42Ca nucleus, populated in the 68 MeV 18O + 30Si reaction, have been studied in a γ-γ-recoil coincidence experiment. The level scheme of 42Ca has been extended up to 13.7 MeV. An elaborate decay pattern with various paths, together with high-quality DCO and polarization
information assigns spins and parities for almost all observed levels. The sequence of non-yrast positive-parity states is
discussed and compared with highly deformed bands in 36Ar and 40Ca.
Received: 26 November 2002 / Accepted: 11 December 2002 / Published online: 18 February 2003
RID="a"
ID="a"e-mail: Malgorzata.Lach@ifj.edu.pl
RID="b"
ID="b"Present address: TRIUMF, Vancouver, Canada.
RID="†"
ID="†"Deceased.
Communicated by D. Schwalm 相似文献
18.
First, we present a simple confining abelian pure gauge theory. Classically, its kinetic term is not positive definite, and
it contains a simple UV regularized F4 interaction. This provokes the formation of a condensate such that, at the saddle point of the effective potential, the wave function normalization constant of the abelian gauge fields vanishes exactly. Then we study SU(2) pure Yang-Mills theory in an abelian gauge and introduce an auxiliary field for a BRST invariant condensate of dimension 2, which renders the charged sector massive. Under simple assumptions its effective
low energy theory reduces to the confining abelian model discussed before, and the VEV of is seen to scale correctly with the renormalization point. Under these assumptions, the confinement condition Z
eff
= 0 also holds for the massive charged sector, which suppresses the couplings of the charged fields to the abelian gauge
bosons in the infrared regime.
Received: 27 November 2002 / Published online: 14 April 2003
RID="a"
ID="a" e-mail: Ulrich.Ellwanger@th.u-psud.fr
RID="b"
ID="b" e-mail: Nicolas.Wschebor@th.u-psud.fr
* Unité Mixte de Recherche - CNRS - UMR 8627 相似文献
19.
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
RID="b"
ID="b"e-mail: sasanka@iitg.ernet.in
RID="c"
ID="c"e-mail: sudipta@iitg.ernet.in 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