共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
Freddy P. Zen Arianto Bobby E. Gunara Triyanta A. Purwanto 《The European Physical Journal C - Particles and Fields》2009,63(3):477-490
The cosmological evolution of an interacting scalar-field model in which the scalar field interacts with dark matter, radiation,
and baryons via Lorentz violation is investigated. We propose a model of interaction through the effective coupling,
[`(b)]\bar{\beta}
. Using dynamical system analysis, we study the linear dynamics of an interacting model and show that the dynamics of critical
points are completely controlled by two parameters. Some results can be mentioned as follows. Firstly, the sequence of radiation,
the dark matter, and the scalar-field dark energy exist and baryons are subdominant. Secondly, the model also allows for the
possibility of having a universe in the phantom phase with constant potential. Thirdly, the effective gravitational constant
varies with respect to time through
[`(b)]\bar{\beta}
. In particular, we consider the simple case where
[`(b)]\bar{\beta}
has a quadratic form and has a good agreement with the modified ΛCDM and quintessence models. Finally, we also calculate the first post-Newtonian parameters for our model. 相似文献
3.
Lorenzo Sebastiani 《The European Physical Journal C - Particles and Fields》2010,65(3-4):547-553
Motivated by Kerner and Man’s fermions tunneling method of dimension 4 black holes, in this paper, we further improve the analysis to investigate Hawking radiation of charged Dirac particles with spin 1/2 from general non-extremal rotating charged black holes with two parameters and a non-zero cosmological constant in minimal five-dimensional gauged supergravity. For space-times with different horizon topology and different dimensions, constructing a set of appropriate γ μ matrices for general covariant Dirac equation is an important technique for the fermion tunneling method. By introducing a set of appropriate matrices γ μ and employing the ansatz for the spin-up spinor field, we successfully recovered the tunneling probability of charged Dirac particles and the expected Hawking temperature of the black hole, which is exactly consistent with that obtained by other methods. Moreover, the fermion tunneling method can be directly applied to the other five-dimensional charged black holes, which strengthens the validity and power of the fermion tunneling method. 相似文献
4.
Xin Zhang 《The European Physical Journal C - Particles and Fields》2009,60(4):661-667
Infinitely cyclic cosmology is often frustrated by the black hole problem. It has been speculated that this obstacle in cyclic
cosmology can be removed by taking into account a peculiar cyclic model derived from loop quantum cosmology or the braneworld
scenario, in which phantom dark energy plays a crucial role. In this peculiar cyclic model, the mechanism of solving the black
hole problem is through tearing up black holes by phantom. However, using the theory of fluid accretion onto black holes,
we show in this paper that there exists another possibility: that black holes cannot be torn up by phantom in this cyclic
model. We discussed this possibility and showed that the masses of black holes might first decrease and then increase, through
phantom accretion onto black holes in the expanding stage of the cyclic universe. 相似文献
5.
Katri Huitu Ritva Kinnunen Jari Laamanen Sami Lehti Sourov Roy Tapio Salminen 《The European Physical Journal C - Particles and Fields》2008,58(4):591-608
In grand-unified theories (GUT), non-universal boundary conditions for the gaugino masses may arise at the unification scale
and may affect the observability of the neutral MSSM Higgs bosons (h/H/A) at the LHC. The implications of such non-universal gaugino masses are investigated for Higgs boson production in the SUSY
cascade decay chain
,
,
,
produced in pp interactions. In the singlet representation with universal gaugino masses only the light Higgs boson can be produced in this
cascade with the parameter region of interest for us, while with non-universal gaugino masses heavy neutral MSSM Higgs boson
production may dominate. The allowed parameter space in the light of the WMAP constraints on the cold dark-matter relic density
is investigated in the above scenarios for gaugino mass parameters. We also demonstrate that combination of representations
can give the required amount of dark matter in any point of the parameter space. In the non-universal case we show that heavy
Higgs bosons can be detected in the cascade studied in parameter regions with the WMAP preferred neutralino relic density. 相似文献
6.
The planar dark spatial soliton supported by the photo-induced isomerization and reorientation of azo-dye Disperse Red 13 was generated in bulk Disperse Red 13 doped poly (methyl methacrylate) using incoherent red light from a continuous-wave He–Ne laser. The guiding of white light by such incoherent dark solitons was investigated for the first time. 相似文献
7.
8.
Howard Baer Andrew D. Box 《The European Physical Journal C - Particles and Fields》2010,68(3-4):523-537
Over almost all of minimal supergravity (mSUGRA or CMSSM) model parameter space, there is a large overabundance of neutralino cold dark matter (CDM). We find that the allowed regions of mSUGRA parameter space which match the measured abundance of CDM in the universe are highly fine-tuned. If instead we invoke the Peccei–Quinn–Weinberg–Wilczek solution to the strong CP problem, then the SUSY CDM may consist of an axion/axino admixture with an axino mass of order the MeV scale, and where mixed axion/axino or mainly axion CDM seems preferred. In this case, fine-tuning of the relic density is typically much lower, showing that axion/axino CDM ( $a\tilde{a}$ CDM) is to be preferred in the paradigm model for SUSY phenomenology. For mSUGRA with $a\tilde{a}$ CDM, quite different regions of parameter space are now DM-favored as compared to the case of neutralino DM. Thus, rather different SUSY signatures are expected at the LHC in the case of mSUGRA with $a\tilde{a}$ CDM, as compared to mSUGRA with neutralino CDM. 相似文献
9.
We review the theoretical aspects of holographic dark energy(HDE) in this paper.Making use of the holographic principle(HP) and the dimensional analysis, we derive the core formula of the original HDE(OHDE) model, in which the future event horizon is chosen as the characteristic length scale. Then, we describe the basic properties and the corresponding theoretical studies of the OHDE model, as well as the effect of adding dark sector interaction in the OHDE model. Moreover, we introduce all four... 相似文献
10.
Sukanta Dutta Ashok Goyal Mamta 《The European Physical Journal C - Particles and Fields》2009,63(2):305-315
We study the one-loop new physics effects to the CP even triple neutral gauge boson vertices γ
⋆
γ
Z, γ
⋆
Z
Z, Z
⋆
Z
γ and Z
⋆
ZZ in the context of Little Higgs models. We compute the contribution of the additional fermions in Little Higgs models in the
framework of direct product groups where [SU(2)×U(1)]2 gauge symmetry is embedded in SU(5) global symmetry and also in the framework of the simple group where SU(N)×U(1) gauge symmetry breaks down to SU(2)
L
×U(1). We calculate the contribution of the fermions to these couplings when T parity is invoked. In addition, we re-examine the MSSM contribution at the chosen point of SPS1a′ and compare with the SM
and Little Higgs models. 相似文献
11.
M. Miyabe M. Oba H. Iimura K. Akaoka Y. Maruyama I. Wakaida 《Applied Physics A: Materials Science & Processing》2010,101(1):65-70
A cerium oxide sample was ablated by 2nd harmonic radiation of Nd:YAG laser at a power density of 0.1 GW/cm2. Time evolution of the ablation plume was investigated by laser absorption time-of-flight (TOF) measurement. It was found
that the ablated ionic plume in vacuum consisted of two components having different velocities whereas the ablated neutral
atoms had mainly a single component. The flow velocity perpendicular to the sample surface in vacuum was determined to be
3.5 km/s for neutral atoms, and 4.7 km/s and 9.3 km/s for singly charged ions. From the detailed plume evolution in ambient
atmosphere with several pressures we obtained some experimental conditions suitable for isotope analysis of atomic cerium. 相似文献
12.
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
13.
We propose a unified scenario to generate the masses of Dirac neutrinos and cold dark matter at the TeV scale, understand the origin of dark energy and explain the matter–antimatter asymmetry of the universe. This model can lead to significant impact on the Higgs searches at LHC. 相似文献
14.
A. Bolshakova I. Boyko G. Chelkov D. Dedovitch A. Elagin M. Gostkin S. Grishin A. Guskov Z. Kroumchtein Yu. Nefedov K. Nikolaev A. Zhemchugov F. Dydak J. Wotschack A. De Min V. Ammosov V. Gapienko V. Koreshev A. Semak Yu. Sviridov E. Usenko V. Zaets 《The European Physical Journal C - Particles and Fields》2009,62(4):697-754
We report on double-differential inclusive cross-sections of the production of secondary protons and charged pions, in the
interactions with a 5% λ
abs thick stationary beryllium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20° <θ<125°. 相似文献
15.
This fairy tale begins with the journey of the famous Zhuang Zhou dreaming of a butterfly: I often do not know whether I am living in a dream, dreaming of a butterfly, or is a butterfly dreaming of me? Furthermore, there is the saying that those who believe it will see it, while for those who see it, it is then too late to believe it. The first thing I believe in is the holographic principle, and the holographic dark energy brought about by the holographic principle. Not until last year, I began... 相似文献
16.
M. Hauer V. V. Begun M. I. Gorenstein 《The European Physical Journal C - Particles and Fields》2008,58(1):83-110
The aim of this paper is to introduce a new technique for the calculation of observables, in particular multiplicity distributions,
in various statistical ensembles at finite volume. The method is based on Fourier analysis of the grand canonical partition
function. A Taylor expansion of the generating function is used to separate contributions to the partition function in their
power in volume. We employ Laplace’s asymptotic expansion to show that any equilibrium distribution of multiplicity, charge,
energy, etc. tends to a multivariate normal distribution in the thermodynamic limit. A Gram–Charlier expansion additionally
allows for the calculation of finite volume corrections. Analytical formulas are presented for the inclusion of resonance
decay and finite acceptance effects directly into the partition function of the system. This paper consolidates and extends
previously published results of the current investigation into the properties of statistical ensembles. 相似文献
17.
D. Nodop J. Rothhardt S. H?drich J. Limpert A. Tünnermann 《Applied physics. B, Lasers and optics》2009,94(3):399-401
We present a Q-switched microchip laser emitting 1064-nm pulses as short as 100 ps synchronized to a cavity dumped femtosecond
laser emitting 800-nm pulses as short as 80 fs. The synchronization is achieved by presaturating the saturable absorber of
the microchip laser with femtosecond pulses even though both lasers emit at widely separated wavelengths. The mean timing
jitter is 40 ps and thus considerably shorter than the pulse duration of the microchip laser. 相似文献
18.
Emmanuel N. Saridakis 《The European Physical Journal C - Particles and Fields》2010,67(1-2):229-235
We formulate Ho?ava–Lifshitz cosmology with an additional scalar field that leads to an effective dark energy sector. We find that, due to the inherited features from the gravitational background, Ho?ava–Lifshitz dark energy naturally presents very interesting behaviors, possessing a varying equation-of-state parameter, exhibiting phantom behavior and allowing for a realization of the phantom divide crossing. In addition, Ho?ava–Lifshitz dark energy guarantees for a bounce at small scale factors and it may trigger the turnaround at large scale factors, leading naturally to cyclic cosmology. 相似文献
19.
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
20.
Carlo Cafaro 《International Journal of Theoretical Physics》2008,47(11):2924-2933
A new information-geometric approach to chaotic dynamics on curved statistical manifolds based on Entropic Dynamics (ED) is
proposed. It is shown that the hyperbolicity of a non-maximally symmetric 6N-dimensional statistical manifold ℳ
s
underlying an ED Gaussian model describing an arbitrary system of 3N degrees of freedom leads to linear information-geometric entropy growth and to exponential divergence of the Jacobi vector
field intensity, quantum and classical features of chaos respectively. 相似文献