共查询到20条相似文献,搜索用时 62 毫秒
1.
Luigi Cappiello Giancarlo D’Ambrosio 《The European Physical Journal C - Particles and Fields》2010,69(1-2):315-329
In holographic QCD the effects of gluonic condensate can be encoded in a suitable deformation of the 5D metric. We develop two different methods for the evaluation of first order perturbative corrections to masses and decay constants of vector resonances in 5D Hard-Wall models of QCD due to small deformations of the metric. They are extracted either from a novel compact form for the first order correction to the vector two-point function, or from perturbation theory for vector bound-state eigenfunctions: the equivalence of the two methods is shown. Our procedures are then applied to flat and to AdS 5D Hard-Wall models; we complement results of existing literature evaluating the corrections to vector decay constant and to two-pion–one-vector couplings: this is particularly relevant to satisfy the sum rules. We concentrate our attention on the effects for the Gasser–Leutwyler coefficients; we show that as in the Chiral Quark model, the addition of the gluonic condensate improves the consistency, the understanding and the agreement with phenomenology of the holographic model. 相似文献
2.
C. I. Christov 《Foundations of Physics》2010,40(6):575-584
We examine the process of the emission of light from an atom that is in a relative translational motion with respect to the
medium at rest in which the electromagnetic excitations propagate. The effect of Lorentz contraction of the of electron orbits
on the emitted frequency is incorporated in the Rydberg formula, as well as the emitter’s Doppler effect is acknowledged.
The result is that the frequency of the emitted light is modified by a factor that is identical with what is called the ‘relativistic
Doppler effect’. The new emission formula is applied for reinterpretation of the Ives-Stilwell experiment and shown that within
the second order of approximation with respect to the speeds of the atom and the ‘absolute speed’ (Earth’s speed relative
to the medium), the absolute motion does not affect the interference. The expression for the modification of the frequency
involves both a first and a second-order term with respect to the speed of the atoms in the cathode tube. The latter turns
out to be quantitatively the same as if the time would have changed its rate in the frame moving with the atoms. Thus, a new
interpretation of the results of this famous experiment is provided without stipulating time dilation. 相似文献
3.
4.
Paul Sorensen 《The European Physical Journal C - Particles and Fields》2009,61(4):829-833
Recent data from heavy ion collisions at RHIC show strong near-side correlations extending over several units of rapidity.
This ridge-like correlation exhibits an abrupt onset with collision centrality. In this talk, I argue that the centrality
and beam-energy dependence of these near-angle correlations could provide access to information about the Quark Gluon Plasma
phase boundary and the Equation of State of nuclear matter. A beam-energy-scan at RHIC will better reveal the true source
of these correlations and should be a high priority at RHIC. 相似文献
5.
We introduce a family of real random polynomials of degree n whose coefficients a
k
are symmetric independent Gaussian variables with variance
, indexed by a real α≥0. We compute exactly the mean number of real roots 〈N
n
〉 for large n. As α is varied, one finds three different phases. First, for 0≤α<1, one finds that
. For 1<α<2, there is an intermediate phase where 〈N
n
〉 grows algebraically with a continuously varying exponent,
. And finally for α>2, one finds a third phase where 〈N
n
〉∼n. This family of real random polynomials thus exhibits a condensation of their roots on the real line in the sense that, for
large n, a finite fraction of their roots 〈N
n
〉/n are real. This condensation occurs via a localization of the real roots around the values
, 1≪k≤n. 相似文献
6.
Hao Wei 《The European Physical Journal C - Particles and Fields》2009,62(3):579-586
Unparticle physics has been an active field since the seminal work of Georgi. Recently, many constraints on unparticles from
various observations have been considered in the literature. In particular, the cosmological constraints on the unparticle
dark component put it in a serious situation. In this work, we try to find a way out of this serious situation, by including
the possible interaction between dark energy and the unparticle dark component. 相似文献
7.
Stefano Re Fiorentin 《Foundations of Physics》2009,39(12):1394-1406
For over a century the definitions of mass and derivations of its relation with energy continue to be elaborated, demonstrating
that the concept of mass is still not satisfactorily understood. The aim of this study is to show that, starting from the
properties of Minkowski spacetime and from the principle of least action, energy expresses the property of inertia of a body.
This implies that inertial mass can only be the object of a definition—the so called mass-energy relation—aimed at measuring
energy in different units, more suitable to describe the huge amount of it enclosed in what we call the “rest-energy” of a
body. Likewise, the concept of gravitational mass becomes unnecessary, being replaceable by energy, thus making the weak equivalence
principle intrinsically verified. In dealing with mass, a new unit of measurement is foretold for it, which relies on the
de Broglie frequency of atoms, the value of which can today be measured with an accuracy of a few parts in 109. 相似文献
8.
G. Cléon T. Amodeo A. Faccinetto P. Desgroux 《Applied physics. B, Lasers and optics》2011,104(2):297-305
In this work, the two-excitation wavelength laser induced incandescence (LII) method has been applied in a low-pressure premixed
methane/oxygen/nitrogen flame (equivalence ratio 2.32) to determine the variation of the ratio of the soot absorption functions
at 532 nm and 1064 nm E(m,532 nm)/E(m,1064 nm) along the flame. This method relies on the comparison of LII signals measured upon two different excitation wavelengths
(here 532 nm and 1064 nm) and with laser fluences selected in such a way that the soot particles are equally laser-heated.
The comparison of the laser fluences at 532 nm and 1064 nm leads to an easy determination of E(m,532 nm)/E(m,1064 nm). The reliability of the method is demonstrated for the first time in a low pressure flame in which the soot nucleation
zone can be spatially resolved and which contains soot particles acting differently with the laser fluence according to their
residence time in the flame. The method is then applied to determine the profile of E(m,532 nm)/E(m,1064 nm) along the flame. A very important decrease of this ratio is observed in the region of nascent soot, while the ratio
remains constant at high distance above the burner. Implication on temperature determination from spectrally resolved measurement
of flame emission is studied. 相似文献
9.
Luis N. Epele Huner Fanchiotti Carlos A. García Canal Vicente Vento 《The European Physical Journal C - Particles and Fields》2009,62(3):587-592
Magnetic monopoles have attracted the attention of physicists since the founding of the electromagnetic theory. Their search
has been a constant endeavor which was intensified when Dirac established the relation between the existence of monopoles
and charge quantization. However, these searches have been unsuccessful. We have recently proposed that monopolium, a monopole–antimonopole
bound state, so strongly bound that it has a relatively small mass, could be easier to find and become an indirect but clear
signature for the existence of magnetic monopoles. Here we extend our previous analysis for its production to two photon fusion
at LHC energies. 相似文献
10.
Hawking radiation from a black hole can be viewed as quantum tunneling of particles through the event horizon. Using this approach we provide a general framework for studying corrections to the entropy of black holes beyond semiclassical approximations. Applying the properties of exact differentials for three variables to the first law thermodynamics, we study charged rotating black holes and explicitly work out the corrections to entropy and horizon area for the Kerr–Newman and charged rotating BTZ black holes. It is shown that the results for other geometries like the Schwarzschild, Reissner-Nordström and anti-de Sitter–Schwarzschild spacetimes follow easily. 相似文献
11.
L. A. Harland-Lang V. A. Khoze M. G. Ryskin W. J. Stirling 《The European Physical Journal C - Particles and Fields》2010,69(1-2):179-199
Central exclusive production (CEP) processes in high-energy proton—(anti)proton collisions offer a very promising framework within which to study both novel aspects of QCD and new physics signals. Among the many interesting processes that can be studied in this way, those involving the production of heavy (c,b) quarkonia and γ γ states have sufficiently well understood theoretical properties and sufficiently large cross sections that they can serve as ‘standard candle’ processes with which we can benchmark predictions for new physics CEP at the CERN Large Hadron Collider. Motivated by the broad agreement with theoretical predictions of recent CEP measurements at the Fermilab Tevatron, we perform a detailed quantitative study of heavy quarkonia (χ and η) and γ γ production at the Tevatron, RHIC and LHC, paying particular attention to the various uncertainties in the calculations. Our results confirm the rich phenomenology that these production processes offer at present and future high-energy colliders. 相似文献
12.
We present analytically the exact solution of the radial Schrödinger equation with the pseudoharmonic oscillator potential in constant positive curvature representation. Exact bound state eigenfunctions and eigenvalues obtained using factorization method. Finally, energy eigenvalues obtained here compared with the results of the theoretical methods in the limit of flat space. 相似文献
13.
André Mischke 《The European Physical Journal C - Particles and Fields》2009,61(4):807-809
We report measurements of the azimuthal angular correlation distribution of heavy-quark decay electrons and open charmed mesons
in pp collisions at
GeV in the STAR experiment at RHIC. This measurement in combination with current theoretical model calculations allows to
extract the relative bottom contribution to the heavy-quark decay electrons, which is important for the interpretation of
the observed strong suppression of the high-p
T electron yield in central Au+Au collisions. 相似文献
14.
In this work we construct the stationary measure of the N species totally asymmetric simple exclusion process in a matrix product formulation. We make the connection between the matrix
product formulation and the queueing theory picture of Ferrari and Martin. In particular, in the standard representation,
the matrices act on the space of queue lengths. For N>2 the matrices in fact become tensor products of elements of quadratic algebras. This enables us to give a purely algebraic
proof of the stationary measure which we present for N=3. 相似文献
15.
Alexander Rybko Senya Shlosman Alexander Vladimirov 《Journal of statistical physics》2009,134(1):67-104
We present an example of a highly connected closed network of servers, where the time correlations do not vanish in the infinite
volume limit. The limiting interacting particle system behaves in a periodic manner. This phenomenon is similar to the continuous
symmetry breaking at low temperatures in statistical mechanics, with the average load playing the role of the inverse temperature. 相似文献
16.
Mohamed Nazih Rhimi Riadh El-Bahi 《International Journal of Theoretical Physics》2008,47(4):1095-1111
The Landau problem of a charged particle in a plane with a uniform perpendicular magnetic field is analysed in two oscillator
modes. The coherent states for the problem have been found out using a general definition of displaced states. The time evolution
and the associated nonadiabatic geometric phase for both initially displaced and non-displaced wave packets have been studied.
The path integral is derived in a simple way through the calculation of Gaussian integrals via the concept of coherent state
wavefunctions. 相似文献
17.
We generalize Minami’s estimate for the Anderson model and its extensions to n eigenvalues, allowing for n arbitrary intervals and arbitrary single-site probability measures with no atoms. As an application, we derive new results about the multiplicity of eigenvalues and Mott’s formula for the ac-conductivity when the single site probability distribution is Hölder continuous. 相似文献
18.
Linsen Zhang Puxun Wu Hongwei Yu 《The European Physical Journal C - Particles and Fields》2011,71(3):1588
In this paper, two modified Ricci models are considered as the candidates of unified dark matter–dark energy. In model one,
the energy density is given by rMR=3Mpl(aH2+b[(H)\dot])\rho_{\mathrm{MR}}=3M_{\mathrm{pl}}(\alpha H^{2}+\beta\dot{H}), whereas, in model two, by
rMR=3Mpl(\fraca6 R+g[(H)\ddot]H-1)\rho_{\mathrm{MR}}=3M_{\mathrm{pl}}(\frac{\alpha}{6} R+\gamma\ddot{H}H^{-1}). We find that they can explain both dark matter and dark energy successfully. A constant equation of state of dark energy
is obtained in model one, which means that it gives the same background evolution as the wCDM model, while model two can give an evolutionary equation of state of dark energy with the phantom divide line crossing
in the near past. 相似文献
19.
P. Osland A. A. Pankov A. V. Tsytrinov 《The European Physical Journal C - Particles and Fields》2010,67(1-2):191-204
Heavy neutral gauge bosons, Z ′s, are predicted by many theoretical schemes of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future high energy colliders. It is quite possible that Z ′s are heavy enough to lie beyond the discovery reach expected at the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z ′ exchanges may occur at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We here discuss in this context the foreseeable sensitivity to Z ′s of fermion-pair production cross sections at an e + e ? linear collider, especially as regards the potential of distinguishing different Z ′ models once such deviations are observed. Specifically, we assess the discovery and identification reaches on Z ′ gauge bosons pertinent to the E 6, LR, ALR and SSM classes of models, that should be attained at the planned International Linear Collider (ILC). With the high experimental accuracies expected at the ILC, the discovery and the identification reaches on the Z ′ models under consideration could be increased substantially. In particular, the identification among the different models could be achieved for values of Z ′ masses in the discovery (but beyond the identification) reach of the LHC. An important role in enhancing such reaches is played by the electron (and possibly the positron) longitudinally polarized beams. Also, although the purely leptonic processes are experimentally cleaner, the measurements of c- and b-quark pair production cross sections are found to carry important, and complementary, information on these searches. 相似文献
20.
We investigate the cosmological evolution of the tachyon and phantom-tachyon scalar field by considering the potential parameter $\Gamma(=\frac{VV''}{V'^{2}}$ ) as a function of another potential parameter $\lambda(=\frac{V'}{\kappa V^{3/2}}$ ), which correspondingly extends the analysis of the evolution of our universe from a two-dimensional autonomous dynamical system to the three-dimensional case. It allows us to investigate the more general situation where the potential is not restricted to an inverse square potential. One particular result is that, apart from the inverse square potential, there are a large number of potentials which can give the scaling and dominant solution when the function Γ(λ) equals 3/2 for one or more values of λ *, as well as that the parameter λ * satisfies certain conditions. We also find that for a class of different potentials the possibilities for the dynamical evolution of the universe are actually the same and therefore undistinguishable. 相似文献