共查询到20条相似文献,搜索用时 31 毫秒
1.
A.?Sibirtsev J.?Haidenbauer S.?Krewald U.?-G.?Mei?ner A.?W.?Thomas 《The European Physical Journal A - Hadrons and Nuclei》2009,41(1):71-84
A Regge model with absorptive corrections is employed in a global analysis of the world data on the reactions
p
p and
n
n for photon energies from 3 to 18GeV. In this region resonance contributions are expected to be negligible so that the available
experimental information on differential cross-sections and single and double polarization observables at - t
2 GeV2allows us to determine the reaction amplitude reliably. The model amplitude is then used to predict observables for photon
energies below 3GeV. A detailed comparison with recent data from the CLAS and CB-ELSA Collaborations in that energy region
is presented. Furthermore, the prospects for determining the radiative decay width via the Primakoff effect from the reaction
p
p are explored. 相似文献
2.
Camelia Mironov Ramona Vogt Gerd J. Kunde 《The European Physical Journal C - Particles and Fields》2009,61(4):893-898
We propose a new method for identifying and isolating
events through semileptonic decays of the
pair. Employing these decay dileptons to tag the jet in a specific kinematic region provides a clean signature of jets associated
with heavy-quark production. The measurement, in both pp and heavy-ion collisions, is essential for addressing heavy-quark fragmentation in vacuum and in a dense medium. We present
next-to-leading order calculations of
production (leading order in
production) in
TeV pp collisions at the LHC and discuss the feasibility of the measurement in heavy-ion collisions at
TeV. 相似文献
3.
Let denote the class of all orthomodular lattices and denote the class of those that are commutator-finite. Also, let denote the class of orthomodular lattices that satisfy the block extension property, those that satisfy the weak block extension property, and those that are locally finite. We show that the following strict containments hold:
Dedicated to the memory of Günter Bruns. 相似文献
4.
Gauhar Abbas B. Ananthanarayan 《The European Physical Journal A - Hadrons and Nuclei》2009,41(1):7-11
We obtain stringent bounds in the 〈r
2
-c plane where these are the scalar radius and the curvature parameters of the scalar K
form factor, respectively, using analyticity and dispersion relation constraints, the knowledge of the form factor from the
well-known Callan-Treiman point , as well as at , which we call the second Callan-Treiman point. The central values of these parameters from a recent determination are accomodated
in the allowed region provided the higher loop corrections to the value of the form factor at the second Callan-Treiman point
reduce the one-loop result by about 3% with . Such a variation in magnitude at the second Callan-Treiman point yields 0.12 fm2
〈r
2
0.21 fm2and 0.56 GeV-4
c
1.47 GeV-4and a strong correlation between them. A smaller value of shifts both bounds to lower values. 相似文献
5.
Shao-Long Chen Xiao-Gang He Xue-Peng Hu Yi Liao 《The European Physical Journal C - Particles and Fields》2009,60(2):317-321
An unparticle
with scaling dimension
has peculiar thermal properties due to its unique phase space structure. We find that the equation of state parameter
, the ratio of pressure to energy density, is given by
providing a new form of energy in our universe. In an expanding universe, the unparticle energy density
evolves dramatically differently from that for photons. For
, even if
at a high decoupling temperature T
D is very small, it is possible to have a large relic density
at present photon temperature T
γ
0, large enough to play the role of dark matter. We calculate T
D and
using photon–unparticle interactions for illustration. 相似文献
6.
7.
Xiang Liu Zhi-Gang Luo Yan-Rui Liu Shi-Lin Zhu 《The European Physical Journal C - Particles and Fields》2009,61(3):411-428
We perform a systematic study of the possible molecular states composed of a pair of heavy mesons such as
,
,
in the framework of the meson exchange model. The exchanged mesons include the pseudoscalar, scalar and vector mesons. Through
our investigation, we find the following results. (1) The structure X(3764) is not a molecular state. (2) There exists strong attraction in the range r<1 fm for the
system with J=0,1. If future experiments confirm Z
+(4051) as a loosely bound molecular state, its quantum number is probably J
P
=0+. Its partner state Φ
**0 may be searched for in the π
0
χ
c1 channel. (3) Vector meson exchange provides strong attraction in the
channel together with pion exchange. A bound state solution may exist with a reasonable cutoff parameter Λ∼1.4 GeV. X(3872) may be accommodated as a molecular state dynamically although drawing a very definite conclusion needs further investigation.
(4) The
molecular state may exist. 相似文献
8.
A recent investigation of the possibility of having a
-symmetric periodic potential in an optical lattice stimulated the urge to generalize non-hermitian quantum mechanics beyond
the case of commutative space. We thus study non-hermitian quantum systems in non-commutative space as well as a
-symmetric deformation of this space. Specifically, a
-symmetric harmonic oscillator together with an iC(x
1+x
2) interaction are discussed in this space, and solutions are obtained. We show that in the
deformed non-commutative space the Hamiltonian may or may not possess real eigenvalues, depending on the choice of the non-commutative
parameters. However, it is shown that in standard non-commutative space, the iC(x
1+x
2) interaction generates only real eigenvalues despite the fact that the Hamiltonian is not
-symmetric. A complex interacting anisotropic oscillator system also is discussed. 相似文献
9.
We calculate the one-photon loop radiative corrections to virtual pion Compton scattering
→
, that subprocess which determines in the one-photon exchange approximation the pion-nucleus bremsstrahlung reaction
Z →
Z
. Ultraviolet and infrared divergencies of the loop integrals are both treated by dimensional regularization. Analytical
expressions for the O() corrections to the virtual Compton scattering amplitudes, A(s, u, Q) and B(s, u, Q) , are derived with their full dependence on the (small) photon virtuality Q from 9 classes of contributing one-loop diagrams. Infrared finiteness of these virtual radiative corrections is achieved
(in the standard way) by including soft photon radiation below an energy cut-off . In the region of low
center-of-mass energies, where the pion-nucleus bremsstrahlung process is used to extract the pion electric and magnetic
polarizabilities, we find radiative corrections up to about -3% for = 5 MeV. Furthermore, we extend our calculation of the radiative corrections to virtual pion Compton scattering
→
by including the leading pion-structure effect in the form of the polarizability difference - . Our analytical results are particularly relevant for analyzing the data of the COMPASS experiment at CERN which aims at
measuring the pion electric and magnetic polarizabilities with high statistics using the Primakoff effect. 相似文献
10.
The H Collaboration 《The European Physical Journal C - Particles and Fields》2003,29(4):497-513
Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of
events in the kinematic range of photon virtualities
and photon-proton centre-of-mass energies
represents an integrated luminosity of
. Jets are defined using the inclusive
algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy ET jet and pseudorapidity
in the domain
and
. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in ET jet, which varies by six orders of magnitude over the measured range, is compared with similar distributions from
colliders at equal and higher energies.Received: 24 February 2003, Revised: 26 May 2003, Published online: 11 July 2003 相似文献
11.
S. Rahaman V.-V. Elomaa T. Eronen U. Hager J. Hakala A. Jokinen A. Kankainen I. D. Moore H. Penttilä S. Rinta-Antila J. Rissanen A. Saastamoinen T. Sonoda C. Weber J. Äystö 《The European physical journal. Special topics》2007,150(1):349-352
The Penning trap mass spectrometer JYFLTRAP was used to measure the atomic masses of radioactive nuclei with an uncertainty
better than 10 keV. The atomic masses of the neutron-deficient nuclei around the
line were measured to improve the understanding of the rp-process path and the SbSnTe cycle. Furthermore, the masses of the
neutron-rich gallium (
) to palladium (
) nuclei have been measured. The physics impacts on the nuclear structure and the r-process paths are reviewed. A better understanding
of the nuclear deformation is presented by studying the pairing energy around
. 相似文献
12.
Liu Yong-Mei 《International Journal of Theoretical Physics》2009,48(8):2372-2378
In this paper, we apply the method of “invariant eigen-operator” to study the Hamiltonian of arbitrary number of coupled identical
oscillators and derive their invariant eigen-operator. The results show that, (1) for the system of arbitrary number of identical
harmonic oscillators by coordinate coupling or momentum coupling, the invariant eigen operator
of system always has the form of
or
; (2) the energy level gap of the system has two kinds of possibilities: one is that gap only related to ω that the frequency of oscillators; another one is that gap not only related to ω that the frequency of oscillators, but also related to the number of the coupling oscillators. 相似文献
13.
Kunji Nakayama 《International Journal of Theoretical Physics》2008,47(7):2065-2094
This paper deals with topos-theoretic truth-value valuations of quantum propositions. Concretely, a mathematical framework
of a specific type of modal approach is extended to the topos theory, and further, structures of the obtained truth-value
valuations are investigated. What is taken up is the modal approach based on a determinate lattice
, which is a sublattice of the lattice
of all quantum propositions and is determined by a quantum state e and a preferred determinate observable R. Topos-theoretic extension is made in the functor category
of which base category
is determined by R. Each true atom, which determines truth values, true or false, of all propositions in
, generates also a multi-valued valuation function of which domain and range are
and a Heyting algebra given by the subobject classifier in
, respectively. All true propositions in
are assigned the top element of the Heyting algebra by the valuation function. False propositions including the null proposition
are, however, assigned values larger than the bottom element. This defect can be removed by use of a subobject semi-classifier.
Furthermore, in order to treat all possible determinate observables in a unified framework, another valuations are constructed
in the functor category
. Here, the base category
includes all
’s as subcategories. Although
has a structure apparently different from
, a subobject semi-classifier of
gives valuations completely equivalent to those in
’s. 相似文献
14.
Zhi-Qing Zhang Zhen-Jun Xiao 《The European Physical Journal C - Particles and Fields》2009,59(1):49-66
We calculate the important next-to-leading-order (NLO) contributions to the B→KK
* decays from the vertex corrections, the quark loops, and the magnetic penguins in the perturbative QCD (pQCD) factorization
approach. The pQCD predictions for the CP-averaged branching ratios are
,
,
and Br(B
0→K
+
K
*−+K
−
K
*+)≈1.3×10−7, which agree well with both the experimental upper limits and the predictions based on the QCD factorization approach. Furthermore,
the CP violating asymmetries of the considered decay modes are also evaluated. The NLO pQCD predictions for
and
decays are
and
. 相似文献
15.
D. V. Petrov M. P. Petrov B. Hilling M. Lemmer M. Imlau 《Applied physics. B, Lasers and optics》2009,95(3):483-488
An impressive linear influence of a magnetic field on optically generated trap-recharging waves (TRW) has been observed in
InP:Fe and GaAs:Cr. The phenomenon appears for the particular orientation of
parallel to the samples’ surface and orthogonal to the direction of the electric field
and wave vector of the TRW
. The results are qualitatively explained taking into account the Lorentz force and a pronounced inhomogeneity of the charge
transport and of the TRW parameters. 相似文献
16.
A.?Sibirtsev J.?Haidenbauer F.?Huang S.?Krewald U.?-G.?Mei?ner 《The European Physical Journal A - Hadrons and Nuclei》2009,40(1):65-75
We present a systematic analysis of backward pion photoproduction for the reactions
p
p and
p
n . Regge phenomenology is applied at invariant collision energies above 3GeV in order to fix the reaction amplitude. A comparision
with older data on - and -photoproduction at = 180° indicates that the high-energy limit as given by the Regge calculation could be reached possibly at energies of around ≃ 3 GeV. In the energy region of
2.5 GeV, covered by the new measurements of
p
p differential cross-sections at large angles at ELSA, JLab, and LEPS, we see no clear signal for a convergence towards the
Regge results. The baryon trajectories obtained in our analysis are in good agreement with those given by the spectrum of
excited baryons. 相似文献
17.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2009,61(2):321-329
We calculate the masses and the pole residues of the
heavy baryons Ω
c
0(css) and Ω
b
−(bss) with the QCD sum rules. The numerical values
GeV (or
GeV) and
GeV (or
GeV) are in good agreement with the experimental data. 相似文献
18.
We calculate the lowest-order cross-section for Dirac magnetic monopole production from photon fusion (
in p
collisions at = 1.96 TeV, pp collisions at = 14 TeV, and we compare
with Drell-Yan (DY) production. We find the total
cross-section is comparable with DY at = 1.96 TeV and dominates DY by a factor > 50 at = 14 TeV. We conclude that both the
and DY processes allow for a monopole mass limit m > 370 GeV based upon the null results of the recent monopole search at the Collider Detector at Fermilab (CDF). We also conclude
that
production is the leading mechanism to be considered for direct monopole searches at the Large Hadron Collider (LHC). 相似文献
19.
E. A. Il’inchik 《Journal of Applied Spectroscopy》2008,75(6):883-891
A set of standard compounds for x-ray photoelectron spectroscopy (XPS): KBH4, NaBPh4, and KBF4 has been identified. Literature data on XPS for salts of the anions , , and , the donor-acceptor complexes LBF3, and also their related compounds was analyzed with a view toward the validity of the data.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 886–895, November–December, 2008. 相似文献
20.
M. Kreuzer R. C. Rashkov M. Schimpf 《The European Physical Journal C - Particles and Fields》2009,60(3):471-480
The non-linear nature of string theory on non-trivial backgrounds, related to the AdS/CFT correspondence, force one to look
for simplifications. Two such simplifications proved to be useful in studying string theory. These are the pp-wave limit,
which describes point-like strings, and the so-called “near-flat space” limit which connects two different sectors of string
theory—pp-wave and “giant magnons”. Recently another example of AdS/CFT duality emerged—AdS
4/CFT
3, which suggests duality between
CS theory and superstring theory on
. In this paper we study the “near-flat space” limit of strings on an
background and discuss possible applications of the limiting theory.
R.C. Rashkov is on leave from Department of Physics, Sofia University, Bulgaria. 相似文献