High Energy Physics - Phenomenology
New submissions
[ showing up to 2000 entries per page: fewer | more ]
New submissions for Tue, 2 Dec 08
- [1] arXiv:0812.0001 [ps, pdf, other]
-
Title: Nonperturbative m_X cut effects in B -> Xs l+ l- observablesComments: 11 pages, 4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
Recently, it was shown that in inclusive B -> Xs l+ l- decay, an angular decomposition provides three independent (q^2 dependent) observables. A strategy was formulated to extract all measurable Wilson coefficients in B -> Xs l+ l- from a few simple integrals of these observables in the low q^2 region. The experimental measurements in the low q^2 region require a cut on the hadronic invariant mass, which introduces a dependence on nonperturbative b quark distribution functions. The associated hadronic uncertainties could potentially limit the sensitivity of these decays to new physics. We compute the nonperturbative corrections to all three observables at leading and subleading order in the power expansion in \Lambda_QCD/m_b. We find that the subleading power corrections give sizeable corrections, of order -5% to -10% depending on the observable and the precise value of the hadronic mass cut. They cause a shift of order -0.05 GeV^2 to -0.1 GeV^2 in the zero of the forward-backward asymmetry.
- [2] arXiv:0812.0064 [ps, pdf, other]
-
Title: Fourth Generation Leptons and Muon $g-2$Comments: 6 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We consider the contributions to $g_\mu-2$ from fourth generation heavy neutral and charged leptons, $N$ and $E$, at the one-loop level. Diagrammatically, there are two types of contributions: boson-boson-$N$, and $E$-$E$-boson in the loop diagram. In general, the effect from $N$ is suppressed by off-diagonal lepton mixing matrix elements. For $E$, we consider flavor changing neutral couplings arising from various New Physics models, which are stringently constrained by $\mu\to e\gamma$. We assess how the existence of a fourth generation would affect these New Physics models.
- [3] arXiv:0812.0072 [ps, pdf, other]
-
Title: Breit-Wigner Enhancement of Dark Matter AnnihilationComments: 4 pages, 4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We point out that annihilation of dark matter in the galactic halo can be enhanced relative to that in the early universe due to a Breit-Wigner tail, if the dark matter annihilates through a pole just below the threshold. This provides a new explanation to the "boost factor" which is suggested by the recent data of the PAMELA, ATIC and PPB-BETS cosmic-ray experiments.
- [4] arXiv:0812.0082 [ps, pdf, other]
-
Title: QCD Corrections to the Radiative Decay B -> X_s gammaAuthors: Andrea FerrogliaComments: 18 pages, 7 figures. Invited review for Modern Physics Letters ASubjects: High Energy Physics - Phenomenology (hep-ph)
In this short review, the calculation of the next-to-next-to-leading order QCD corrections to the inclusive radiative decay B -> X_s gamma is described. I summarize the salient features of the calculational framework adopted, discuss the results obtained in the last few years, and indicate the technical tools that made the NNLO calculations possible. I conclude by comparing the current NNLO theoretical estimate for the branching ratio with the experimental measurement and by briefly discussing the size and origin of the residual theoretical uncertainty.
- [5] arXiv:0812.0084 [ps, pdf, other]
-
Title: Neutrino masses and mixing, lightest neutralino decays and a solution to the $\mu$ problem in supersymmetryComments: 28 pages, 19 figures, RevTeX4Subjects: High Energy Physics - Phenomenology (hep-ph)
We examine in detail the neutrino masses and mixing patterns in an extension of the minimal supersymmetric standard model with three gauge-singlet neutrinos and R-parity violation. The Majorana masses for the gauge-singlet neutrinos as well as the usual $\mu$-term for the Higgs superfields are generated at the electroweak scale through the vacuum expectation values of the singlet sneutrinos. The resulting effective mass matrix for the three light neutrinos have contributions from the seesaw mechanism involving the singlet neutrinos as well as due to the mixing with the heavy neutralinos. We show that even with flavour diagonal neutrino Yukawa couplings, the global data on three-flavour neutrinos can be well accounted for in this scenario, at the tree level. We also analyze the mixing in the chargino and the Higgs sector and calculate the decays of the lightest supersymmetric particle in this model. The decay branching ratios show certain correlations with the neutrino mixing angles, which can be tested at the LHC. Some other phenomenological implications of such a model have been discussed.
- [6] arXiv:0812.0087 [ps, pdf, other]
-
Title: Consequences of a unified, anarchical model of fermion masses and mixingsComments: 31 pages, 6 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We show that most features of the mass and mixing pattern of the second and third SM fermion families can be accounted for without making use of flavour symmetries or other types of flavour dynamics. We discuss the implications for flavour phenomenology, in particular for the $\tau\to\mu\gamma$ decay rate, and comment on LFV effects at colliders. We show that the model can be embedded in a full SO(10) supersymmetric GUT in 5 dimensions that preserves the successful MSSM gauge coupling unification prediction for $\alpha_s$. Interesting features of this embedding are i) the connection of one of the hierarchy parameters with the strong coupling assumption, ii) the absence of KK threshold effects on the $\alpha_s$ prediction at one loop, and iii) the shift of the GUT scale up to about $10^{17}\GeV$. Proton decay is under control, also due to the larger GUT scale. A large atmospheric angle for normal hierarchical neutrinos is obtained in an unusual way.
- [7] arXiv:0812.0120 [ps, pdf, other]
-
Title: Leptogenesis Scenarios via Non-Thermally Produced Right-handed Neutrino and Sneutrino in Supersymmetric Seesaw ModelComments: 28 pages, 7 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
Leptogenesis via non-thermally produced right-handed (s)neutrino is surveyed systematically. In particular, we focus on leptogenesis scenarios from right-handed (s)neutrino produced by the decay of inflaton and from right-handed sneutrino condensate. We also briefly discuss leptogenesis after sneutrino inflation. Resultant lepton asymmetry and constraints from the gravitino problem are studied in detail. Conditions of the successful leptogenesis via these scenarios are clearly shown. It is also shown how these leptogenesis scenarios depend on the parameters, the inflaton decay rate (the reheating temperature), the right-handed neutrino mass, the lightest neutrino mass, and the constraint from the gravitino problem.
- [8] arXiv:0812.0187 [ps, pdf, other]
-
Title: Nucleon and gamma N -> Delta lattice form factors in a constituent quark modelComments: 5 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
A covariant quark model, based both on the spectator formalism and on Vector Meson Dominance, and previously calibrated by the physical data, is here extended to the unphysical region of the lattice data by means of one single extra adjustable parameter - the constituent quark mass in the chiral limit. We calculated the Nucleon (N) and the Gamma N -> Delta form factors in the universe of values for that parameter described by quenched lattice QCD. A qualitative description of the Nucleon and Gamma N -> Delta form factors lattice data is achieved for light pion masses.
- [9] arXiv:0812.0219 [ps, pdf, other]
-
Title: Neutrino Signals from Annihilating/Decaying Dark Matter in the Light of Recent Measurements of Cosmic Ray Electron/Positron FluxesComments: 4 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
The excess of cosmic-ray electron and positron fluxes measured by the PAMELA satellite and ATIC balloon experiments may be interpreted as the signals of the dark matter annihilation or decay. In this letter we show that the dark matter annihilation/decay which reproduces the electron/positron excess also naturally yields a significant amount of neutrinos. Future kilometer-square size experiments may confirm such a scenario, or even the Super-Kamiokande results may already give stringent constraints.
- [10] arXiv:0812.0230 [ps, pdf, other]
-
Title: CP asymmetry in $B^{+}\to K^+\pi^{0}$ and New PhysicsAuthors: Namit MahajanComments: Revtex, 5 pages including 3 eps figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
The CP asymmetry in $B^0\to K^+\pi^-$ is expected to be similar to that in $B^+\to K^+\pi^0$. The experimental data however show $\sim 5\sigma$ difference between the two, leading to the so called $\Delta {A}_{K\pi}$ puzzle. Employing sum rule(s) following from (approximate) flavour symmetry, we show that it is possible to accommodate the observed experimental values within the standard model (SM) for a narrow range of parameters. Sub-leading terms can bring the theoretical predictions in better agreement with the data. Resolution via modified electroweak penguin contributions is possible for a large CP violating phase generated by the new physics. However, the data on polarization in $B\to VV(T)$, $B_s$-$\bar{B}_s$ mixing (and large CP phase) and $B^+\to\tau^+\nu_{\tau}$ rate can not be simultaneously accommodated within SM or new physics with only enhanced electroweak penguins. A plausible resolution to these, and not spoiling the $B\to K\pi$ rates and asymmetries, could be a general two Higgs doublet model.
- [11] arXiv:0812.0232 [ps, pdf, other]
-
Title: Higher Angular Momentum Mixing in a Non-spherical Color Superconductor with Time Reversal Invariance ViolationComments: 6 pages, 1 figure with RevtexSubjects: High Energy Physics - Phenomenology (hep-ph)
The angular momentum mixing in a non-spherical CSC with nonzero azimuthal quantum number and therefore violating time reversal invariance has been examined. The mixing is bound to occur because of the equal strength of the pairing potential mediated by one-gluon exchange for all partial waves to the leading order QCD running coupling constant and the nonlinearity of the gap equation. The free energy with mixing is lower than that with p-wave pairing only, but still higher than that of the spherical CSL state.
- [12] arXiv:0812.0249 [ps, pdf, other]
-
Title: F-Term Hybrid Inflation Followed by Modular InflationAuthors: C. PallisComments: To appear in the proceedings of the Spanish Relativity Meeting (ERE 2008) 15-20 September 2008, Salamanca, SpainSubjects: High Energy Physics - Phenomenology (hep-ph)
We consider the well motivated model of the (standard) supersymmetric F-term hybrid inflation (FHI) which can be realized close to the grand unification scale. The predicted scalar spectral index $n_s$ cannot be smaller than 0.98 and can exceed unity including corrections from minimal supergravity, if the number of e-foldings corresponding to the pivot scale $k_*=0.002/{\rm Mpc}$ is around 50. These results are marginally consistent with the fitting of the Wilkinson microwave anisotropy probe data by the standard power-law cosmological model with cold dark matter and a cosmological constant. However, $n_s$ can be reduced by restricting the number of e-foldings that $k_*$ suffered during FHI. The additional e-foldings required for solving the horizon and flatness problems can be generated by a subsequent stage of fast-roll [slow-roll] modular inflation realized by a string modulus which does [does not] acquire effective mass before the onset of modular inflation.
- [13] arXiv:0812.0265 [ps, pdf, other]
-
Title: CP violation in charged Higgs boson decaysComments: a talk presented at the workshop "Prospects for Charged Higgs Discovery at Colliders", September 16-19 2008, Uppsala Universtity, Sweden, 6 pages with 3 figures. to appear in the Proceedings of the workshopSubjects: High Energy Physics - Phenomenology (hep-ph)
CP violation in H^\pm decays into the three possible decay modes into ordinary particles, 1) H^\pm \to tb, 2) H^\pm \to \nu \tau and 3) H^\pm \to W^\pm h^0 is considered. Analytic expressions and numerical results for the CP violating decay rate asymmetries in the MSSM are obtained. Increasing \tan\beta the asymmetries for the fermionic decays, H^\pm \to tb and H^\pm \to \nu \tau, decrease and it increases for H^\pm \to W^\pm h^0. The asymmetry of H^\pm \to tb is most sensitive to the phase of $A_t and can go up to 20%, the asymmetries of 2) and 3) depend mainly on the phases of A_\tau and M_1. The asymmetry of 2) is smaller than 0.5% and of 3) can reach up to 2%.
- [14] arXiv:0812.0270 [ps, pdf, other]
-
Title: Varying and inverting the mass hierarchy in collisional energy lossComments: 10 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
Heavy ion collisions at RHIC and at the LHC give access to the medium-induced suppression patterns of heavy-flavored single inclusive hadron spectra at high transverse momentum. This opens novel opportunities for a detailed characterization of the medium produced in the collision. In this note, we point out that the capacity of a QCD medium to absorb the recoil of a partonic projectile is an independent signature, which may differ for different media at the same density. In particular, while the mass hierarchy (i.e., the projectile mass dependence) of radiative energy loss depends solely on a property of the projectile, the mass hierarchy of collisional energy loss depends significantly on properties of the medium. By varying these properties in a class of models, we find that the mass hierarchy of collisional parton energy loss can be modified considerably and can even be inverted, compared to that of radiative parton energy loss. This may help to disentangle the relative strengths of radiative and collisional contributions to jet quenching, and it may be employed to constrain properties of the produced QCD medium beyond its density.
- [15] arXiv:0812.0294 [ps, pdf, other]
-
Title: Signatures of NP models in top FCNC decay t --> c(u) l+ l-Comments: 12 pages, 9 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
Among other roles the LHC will play a role of the top "factory" and it will give us unique possibility to study new physics signatures in different ways. Many scenarios of new physics allow top quark FCNC decays. Using most general model independent Lagrangian of new physics we investigate possible experimental signals of new physics in t --> c(u) l+ l- FCNC top decays. We find that measurement of two possible asymmetries might give very important and interesting information of NP. It is particularly interesting to use them to discriminate among variety on NP scenarios. We consider also contributions of the interference between scalar and vector mediators of the FCNC decays.
- [16] arXiv:0812.0296 [ps, pdf, other]
-
Title: On distinguishing the direct and spontaneous CP violation in 2HDMComments: 6 pages; to appear in the proceedings of the "Prospects for Charged Higgs Discovery at Colliders", 16-19 September 2008, Uppsala, SwedenSubjects: High Energy Physics - Phenomenology (hep-ph)
The most general Two Higgs Doublet Model (2HDM) allows both for the explicit and the spontaneous CP violation in the scalar sector. Here we discuss CP violation in terms of basis-independent quantities and show how using two different sets of known CP-odd weak-basis invariants one can distinguish between CP conservation, explicit CP violation and spontaneous CP violation. The special case of CP violation without CP mixing, in which the neutral Higgs gauge boson interaction respects CP while Higgs self-interaction violates CP symmetry, is also presented.
- [17] arXiv:0812.0307 [ps, pdf, other]
-
Title: Color Octet Scalar Bound States at the LHCComments: 13 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
One possible extension of the Standard Model scalar sector includes SU(2)_L doublet scalars that are color octets rather than singlets. We focus on models in which the couplings to fermions are consistent with the principle of minimal flavor violation (MFV), in which case these color octet scalars couple most strongly to the third generation of quarks. When the Yukawa coupling of color octet scalars to Standard Model fermions is less than unity, these states can live long enough to bind into color-singlet spin-0 hadrons, which we call octetonia. In this paper, we consider the phenomenology of octetonia at the Large Hadron Collider (LHC). Predictions for their production via gluon-gluon fusion and their two-body decays into Standard Model gauge bosons, Higgs bosons, and \bar{t}t are presented.
- [18] arXiv:0812.0308 [ps, pdf, other]
-
Title: Dark matter and sub-GeV hidden U(1) in GMSB modelsComments: 7 pages, 4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
Motivated by the recent PAMELA and ATIC data, one is led to the scenario with heavy vector-like dark matter in association with a hidden $U(1)_X$ sector below GeV scale. Realizing this idea in the context of gauge mediated supersymmetry breaking (GMSB), a heavy scalar component charged under $U(1)_X$ is found to be a good dark matter candidate which can be searched for direct scattering mediated by the Higgs boson and/or by the hidden gauge boson. The latter turns out to put a stringent bound on the kinetic mixing parameter between $U(1)_X$ and $U(1)_Y$: $\theta \lesssim 10^{-6}$. For the typical range of model parameters, we find that the decay rates of the ordinary lightest neutralino into hidden gauge boson/gaugino and photon/gravitino are comparable, and the former decay mode leaves displaced vertices of lepton pairs and missing energy with distinctive length scale larger than 20 cm for invariant lepton pair mass below 0.5 GeV. An unsatisfactory aspect of our model is that the Sommerfeld effect cannot enhance the galactic dark matter annihilation by more than 60 for the dark matter mass below TeV.
- [19] arXiv:0812.0315 [ps, pdf, other]
-
Title: Masses and widths of scalar tetraquarks with hidden bottomComments: 7 pages, latexSubjects: High Energy Physics - Phenomenology (hep-ph)
The relativistic four-quark equations are found in the framework of coupled-channel formalism. The dynamical mixing of the meson-meson states with the four-quark states is considered. The four-quark amplitudes of the tetraquarks with hidden bottom, including u, d, s and bottom quarks, are constructed. The poles of these amplitudes determine the masses and widths of tetraquarks.
- [20] arXiv:0812.0323 [ps, pdf, other]
-
Title: Pion form factor from local-duality QCD sum ruleComments: Talk given at the 8-th Conference "Quark Confinement and the Hadron Spectrum", Mainz, Germany, 1-6 September 2008Subjects: High Energy Physics - Phenomenology (hep-ph)
We present our recent results for the pion elastic form factor [1] obtained within a local-duality three-point sum rule (a Borel sum rule in the limit of an infinite Borel parameter). Our analysis includes the O(1) and O(\alpha_s) contributions and is therefore applicable in a broad range of spacelike momentum transfers. Our results demonstrate in essentially model-independent way that the O(1) term, which provides the subleading 1/Q^4 power correction at asymptotically large momentum transfers, contributes more than half of the pion form factor in the region Q^2 \le 20 GeV^2. To probe the accuracy of local-duality sum rules for form factors, we apply precisely the same procedures to extract the form factor in a quantum-mechanical potential model. Comparison of the exact form factor known in this model with the result of the sum-rule calculation gives a probe of the systematic error of the method. In our example this error is found to be at the level of 10-20%. We expect similar systematic errors for form factors obtained from local-duality sum rules in QCD.
- [21] arXiv:0812.0342 [ps, pdf, other]
-
Title: Gauge coupling unification, the GUT scale, and magic fieldsComments: 14 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We consider field sets that do not form complete SU(5) multiplets, but exactly preserve the one-loop MSSM prediction for $\alpha_3(M_Z)$ independently of the value of their mass. Such fields can raise the unification scale in different ways, through a delayed convergence of the gauge couplings, a fake unified running below the GUT scale, or a postponed unification after a hoax crossing at a lower scale. The $\alpha_3(M_Z)$ prediction is independent of the mass of the new fields, while the GUT scale often is not, which allows to vary the GUT scale. Such "magic" fields represent a useful tool in GUT model building. For example, they can be used to fix gauge coupling unification in certain two step breakings of the unified group, to suppress large KK thresholds in models with extra dimensions, or they can be interpreted as messengers of supersymmetry breaking in GMSB models.
- [22] arXiv:0812.0344 [ps, pdf, other]
-
Title: Electromagnetic corrections in eta --> 3 pi decaysComments: 21 pages, 11 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
We re-evaluate the electromagnetic corrections to eta --> 3 pi decays at next-to-leading order in the chiral expansion, arguing that effects of order e^2(m_u-m_d) disregarded so far are not negligible compared to other contributions of order e^2 times a light quark mass. Despite the appearance of the Coulomb pole in eta --> pi+ pi- pi0 and cusps in eta --> 3 pi0, the overall corrections remain small.
- [23] arXiv:0812.0353 [ps, pdf, other]
-
Title: On the Soft-Gluon Resummation in Top Quark Pair Production at Hadron CollidersComments: 11 pages, 1 figureSubjects: High Energy Physics - Phenomenology (hep-ph)
We uncover a contribution to the NLO/NLL threshold resummed total cross section for top quark pair production at hadron colliders, which has not been taken into account in earlier literature. We derive this contribution - the difference between the singlet and octet hard (matching) coefficients - in exact analytic form. The numerical impact of our findings on the Sudakov resummed cross section turns out to be large, and comparable in size to the current estimates for the theoretical uncertainty of the total cross section. A rough estimate points toward a few percent decrease of the latter at the LHC.
- [24] arXiv:0812.0359 [ps, pdf, other]
-
Title: Center vortices, the functional Schrodinger equation, and CSBAuthors: John M. CornwallComments: 28 pages, i figure. Presented at Approaches to QCD, Oberwoelz, Austria, Sept. 2008Subjects: High Energy Physics - Phenomenology (hep-ph)
The functional Schrodinger equation (FSE) for QCD gives a unique perspective on generation of a gluon mass m, as required for center vortices. The FSE, which yields a special d=3 gauge action, combined with lattice calculations strictly in d=3 give a value for the dimensionless ratio of d=3 coupling to mass g_3^2/m. From this we infer a reasonably accurate value for the d=4 running coupling g^2(0) in the region of low momentum where it is nearly constant. The result, consistent with other estimates, is too low to drive chiral symmetry breaking (CSB) for quarks in a standard gap equation that has no explicit confinement effects. We recall and improve on old work showing that confinement implies CSB for quarks, and consider CSB for test (that is, quenched) Dirac fermions in the adjoint representation. Here the previously-found value of $g^2(0)$ is large enough to drive CSB in a gap equation, which we relate to the presence of center vortices (non-confining, for the adjoint) and nexuses that drive fermionic zero modes. We discuss the extension of adjoint CSB to finite temperature.
Cross-lists for Tue, 2 Dec 08
- [25] arXiv:0811.2262 (cross-list from hep-th) [ps, pdf, other]
-
Title: Holographic Responses of Fermion MatterComments: 21 page, 1 figure, harvmacSubjects: High Energy Physics - Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics - Phenomenology (hep-ph)
We consider the $D4-D8-\overline{D8}$ brane system which serves as ultraviolet completion of the Nambu-Jona-Lasinio model, where the only degrees of freedom carrying baryon charge are fermions. By turning on chemical potential for this charge one may expect the formation of the Fermi liquid ground state. At strong coupling we use the dual holographic description to investigate the responses of the system to small perturbations. In the chirally symmetric phase we find that the density dependent part of the heat capacity vanishes linearly with temperature. We also observe a zero sound excitation in the collisionless regime, whose speed is equal to that of normal sound in the hydrodynamic regime. Both the linear dependence of the heat capacity and the existence of zero sound are properties of the Fermi liquid ground state. We also compute the two-point function of the currents at vanishing frequency but do not find any singularities at finite values of the momentum.
- [26] arXiv:0811.3911 (cross-list from astro-ph) [ps, pdf, other]
-
Title: CMBPol Mission Concept Study: A Mission to Map our OriginsAuthors: Daniel Baumann, Asantha Cooray, Scott Dodelson, Joanna Dunkley, Aurélien A. Fraisse, Mark G. Jackson, Al Kogut, Lawrence M. Krauss, Kendrick M. Smith, Matias ZaldarriagaComments: 6 pages, 3 figuresSubjects: Astrophysics (astro-ph); High Energy Physics - Phenomenology (hep-ph)
Quantum mechanical metric fluctuations during an early inflationary phase of the universe leave a characteristic imprint in the polarization of the cosmic microwave background (CMB). The amplitude of this signal depends on the energy scale at which inflation occurred. Detailed observations by a dedicated satellite mission (CMBPol) therefore provide information about energy scales as high as $10^{15}$ GeV, twelve orders of magnitude greater than the highest energies accessible to particle accelerators, and probe the earliest moments in the history of the universe. This summary provides an overview of a set of studies exploring the scientific payoff of CMBPol in diverse areas of modern cosmology, such as the physics of inflation, gravitational lensing and cosmic reionization, as well as foreground science and removal .
- [27] arXiv:0811.4484 (cross-list from gr-qc) [ps, pdf, other]
-
Title: Graviton, ghost and instanton condensation on horizon scale of the Universe. Dark energy as a macroscopic effect of quantum gravityAuthors: Leonid Marochnik (1), Daniel Usikov, Grigory Vereshkov (2) ((1) University of Maryland, College Park, (2) Research Institute of Physics, Southern Federal University)Comments: 92 pp, 4 figs, REVTeX 4Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics (astro-ph); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We show that cosmological acceleration, Dark Energy (DE) effect is a consequence of the zero rest mass, conformal non-invariance of gravitons, and 1-loop finiteness of quantum gravity (QG). The effect is due to graviton-ghost condensates arising from the interference of quantum coherent states. The theory is constructed as follows: De Witt-Faddeev-Popov gauged path integral -> factorization of classical and quantum variables -> transition to the 1-loop approximation -> choice of ghost sector, satisfying 1-loop finiteness of the theory off the mass shell. The Bogolyubov-Born-Green-Kirckwood-Yvon (BBGKY) chain for the spectral function of gravitons renormalized by ghosts is used to build a theory of gravitons in the isotropic Universe. We found three exact solutions of the equations that describe virtual graviton and ghost condensates as well as condensates of instanton fluctuations. Exact solutions correspond to various condensates with different graviton-ghost compositions. The formalism of the BBGKY chain takes into account the contribution of non-relativistic matter in the formation of a common self-consistent gravitational field. It is shown that the era of non-relativistic matter dominance must be replaced by an era of dominance of graviton-ghost condensate. Pre-asymptotic state of DE is a condensate of virtual gravitons and ghosts with a constant conformal wavelength. The asymptotic state predicted by the theory is a graviton-ghost condensate of constant physical wavelength in the De Sitter space. Such DE phenomenon is presented in the form of the model that interpolates the exact solutions of equations of 1-loop QG. Processing of observational DE data extracted from the Hubble diagram for supernovae SNIa suggests that the graviton-ghost condensate is an adequate variable component of DE.
- [28] arXiv:0811.4516 (cross-list from nucl-th) [ps, pdf, other]
-
Title: Formation of eta-mesic nuclei by (pi,N) reaction and N^*(1535) in mediumComments: 12 pages, 10 figuresSubjects: Nuclear Theory (nucl-th); High Energy Physics - Phenomenology (hep-ph)
We calculate formation spectra of eta-nucleus systems in (pi,N) reactions with nuclear targets, which can be performed at existing and/or forthcoming facilities, including J-PARC, in order to investigate eta-nucleus interactions. Based on the N^*(1535) dominance in the eta N system, eta-mesic nuclei are suitable systems for study of in-medium properties of the N^*(1535) baryon resonance, such as reduction of the mass difference of N and N^* in nuclear medium, which affects level structure of the eta and N^*-hole modes. We find that clear information on the in-medium N^*- and eta-nucleus interactions can be obtained through the formation spectra of the eta-mesic nuclei. We also discuss the experimental feasibilities by showing several spectra of (pi,N) reactions calculated with possible experimental settings. Coincident measurements of pi N pairs from the N^* decays in nuclei help us to reduce backgrounds.
- [29] arXiv:0811.4607 (cross-list from hep-th) [ps, pdf, other]
-
Title: Tachyon-Dilaton-induced Inflation as an alpha'-resummed String BackgroundComments: 35 pages Latex, three eps figures incorporatedSubjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Within the framework of a novel functional method on the world-sheet of the string, we discuss simple but re-summed (in the Regge slope) inflationary scenarios in the context of closed Bosonic strings, living in four target-space dimensions, in the presence of non-trivial tachyon, dilaton and graviton cosmological backgrounds. The inflationary solutions are argued to guarantee the vanishing of the corresponding Weyl anomaly coefficients in a given world-sheet renormalization scheme, thereby ensuring conformal invariance of the corresponding sigma-model to all orders in the Regge slope. The key property is the requirement of "homogeneity" of the corresponding Weyl anomaly coefficients. Inflation entails appropriate relations between the dilaton and tachyon field configurations, whose form can lead to either a de Sitter vacuum, incompatible though (due to the cosmic horizons) with the perturbative string scattering amplitudes, or to cosmic space-times involving brief inflationary periods, interpolating smoothly between power-law and/or Minkowski Universes. The latter situation is characterized by well-defined scattering amplitudes, and is thus compatible with a perturbative string framework. It is this scenario that we consider a self-consistent ground state in our framework, which is based on local field redefinitions of background fields.
- [30] arXiv:0811.4617 (cross-list from hep-th) [ps, pdf, other]
-
Title: Open Wilson Lines and Chiral Condensates in Thermal Holographic QCDComments: 45 pages, 18 figuresSubjects: High Energy Physics - Theory (hep-th); High Energy Physics - Phenomenology (hep-ph)
We investigate various aspects of a proposal by Aharony and Kutasov arXiv:0803.3547 [hep-th] for the gravity dual of an open Wilson line in the Sakai-Sugimoto model or its non-compact version. In particular, we use their proposal to determine the effect of finite temperature, as well as background electric and magnetic fields, on the chiral symmetry breaking order parameter. We also generalize their prescription to more complicated worldsheets and identify the operators dual to such worldsheets.
- [31] arXiv:0812.0345 (cross-list from physics.ins-det) [ps, pdf, other]
-
Title: Probing For New Physics and Detecting non linear vacuum QED effects using gravitational wave interferometer antennasSubjects: Instrumentation and Detectors (physics.ins-det); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
Low energy non linear QED effects in vacuum have been predicted since 1936 and have been subject of research for many decades. Two main schemes have been proposed for such a 'first' detection: measurements of ellipticity acquired by a linearly polarized beam of light passing through a magnetic field and direct light-light scattering. The study of the propagation of light through an external field can also be used to probe for new physics such as the existence of axion-like particles and millicharged particles. Their existence in nature would cause the index of refraction of vacuum to be different from unity in the presence of an external field and dependent of the polarization direction of the light propagating. The major achievement of reaching the project sensitivities in gravitational wave interferometers such as LIGO an VIRGO has opened the possibility of using such instruments for the detection of QED corrections in electrodynamics and for probing new physics at very low energies. In this paper we discuss the difference between direct birefringence measurements and index of refraction measurements. We propose an almost parasitic implementation of an external magnetic field along the arms of the VIRGO interferometer and discuss the advantage of this choice in comparison to a previously proposed configuration based on shorter prototype interferometers which we believe is inadequate. Considering the design sensitivity in the strain, for the near future VIRGO+ interferometer, of $h<2\cdot10^{-23} \frac{1}{\sqrt{\rm Hz}}$ in the range 40 Hz $- 400$ Hz leads to a variable dipole magnet configuration at a frequency above 20 Hz such that $B^{2}D \ge 13000$ T$^{2}$m/$\sqrt{\rm Hz}$ for a `first' vacuum non linear QED detection.
Replacements for Tue, 2 Dec 08
- [32] arXiv:hep-ph/0409081 (replaced) [ps, pdf, other]
-
Title: Extraction of the charged pion polarizabilities from radiative charged pion photoproduction in Heavy Baryon Chiral Perturbation TheoryComments: 17 pages, 11 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
- [33] arXiv:physics/0612173 (replaced) [ps, pdf, other]
-
Title: Observable effects caused by vacuum pair creation in the field of high-power optical lasersAuthors: David B. Blaschke, Andrey V. Filatov, Irina A. Egorova, Alexander V. Prozorkevich, Stanislav A. SmolyanskyComments: 7 pages, 7 figures; typos corrected, Eq.(16) corrected, reference addedJournal-ref: Saratov Fall Meeting 2006: Laser Physics and Photonics, Spectroscopy and Molecular Modeling VII, Proceedings of SPIE, V.6537, (2007) p.653708Subjects: Optics (physics.optics); High Energy Physics - Phenomenology (hep-ph); Plasma Physics (physics.plasm-ph)
- [34] arXiv:0709.0979 (replaced) [ps, pdf, other]
-
Title: Rare Semileptonic Decays of Heavy Mesons with Flavor SU(3) SymmetryComments: 4 pages and 1 figure, accepted by European Physical Journal CSubjects: High Energy Physics - Phenomenology (hep-ph)
- [35] arXiv:0802.2642 (replaced) [ps, pdf, other]
-
Title: Signal of New Physics and Chemical Composition of Matter in Core Crossing NeutrinosAuthors: Wei LiaoComments: 10 pages, 4 figuresJournal-ref: Eur. Phys. J. C57, 763(2008)Subjects: High Energy Physics - Phenomenology (hep-ph)
- [36] arXiv:0803.0696 (replaced) [ps, pdf, other]
-
Title: Can one measure C-odd asymmetry in e+e- --> pi+pi-Comments: 4 pages, 2 figures, 1 Table (revised version)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex)
- [37] arXiv:0804.0140 (replaced) [ps, pdf, other]
-
Title: Upper bound on the cutoff in lattice Electroweak theoryComments: Latex, 22 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Lattice (hep-lat)
- [38] arXiv:0804.1822 (replaced) [ps, pdf, other]
-
Title: A possible signature of new physics at BES-IIIComments: 5 pages, 3 figures, mini-review, accepted by Chinese Physics C (HEP & NP)Subjects: High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
- [39] arXiv:0805.0233 (replaced) [ps, pdf, other]
-
Title: Possible Method for Measuring the Proton Form Factors in Processes with and without Proton Spin FlipComments: 7 pages, revtex4Journal-ref: Pisma Zh.Eksp.Teor.Fiz.,vol.88:No.8, pp.555-560,2008; JETP Letters,vol.88:No.8, pp.481-486,2008Subjects: High Energy Physics - Phenomenology (hep-ph)
- [40] arXiv:0807.1309 (replaced) [ps, pdf, other]
-
Title: A new correlation method to identify and separate charm and bottom production processes at RHICAuthors: Andre MischkeComments: 6 pages, 6 figures, as accepted by Phys. Lett. BSubjects: High Energy Physics - Phenomenology (hep-ph)
- [41] arXiv:0808.2016 (replaced) [ps, pdf, other]
-
Title: Three-flavour neutrino oscillation updateComments: 11 pages, 4 figures, matches published versionJournal-ref: NewJ.Phys.10:113011,2008Subjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics (astro-ph); High Energy Physics - Experiment (hep-ex)
- [42] arXiv:0808.3236 (replaced) [ps, pdf, other]
-
Title: Coset Space Dimensional Reduction and Wilson Flux Breaking of Ten-Dimensional N=1, E(8) Gauge TheoryComments: 45 pages, 2 figures, 10 tables, uses xy.sty, longtable.sty, ltxtable.sty, (a shorter version will be published in Eur. Phys. J. C)Subjects: High Energy Physics - Theory (hep-th); High Energy Physics - Phenomenology (hep-ph)
- [43] arXiv:0808.3371 (replaced) [ps, pdf, other]
-
Title: Number of the QCD critical points with neutral color superconductivityComments: 14 pages, 10 figures. The discussion and figures on chromomagnetic instability addedSubjects: High Energy Physics - Phenomenology (hep-ph)
- [44] arXiv:0811.1345 (replaced) [ps, pdf, other]
-
Title: Quark Forces from Hadron SpectroscopyComments: 4 pages, 4 figures; improved figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
- [45] arXiv:0811.3050 (replaced) [ps, pdf, other]
-
Title: Gauge Covariance Relations and the Fermion Propagator in Maxwell-Chern-Simons QED3Comments: 13 pages, 4 figures. Published version. V2, References correctedJournal-ref: J. Phys. A: Math. Theor. 41 (2008) 505401Subjects: High Energy Physics - Phenomenology (hep-ph); Mesoscopic Systems and Quantum Hall Effect (cond-mat.mes-hall); High Energy Physics - Theory (hep-th)
- [46] arXiv:0811.3411 (replaced) [ps, pdf, other]
-
Title: Neutrino Mass Hierarchy and neutron-anti-neutron Oscillation from BaryogenesisComments: 23 pages and seven figures; Fifure 4 replaced; references updated; typos correctedSubjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics (astro-ph); High Energy Physics - Experiment (hep-ex)
- [47] arXiv:0811.3719 (replaced) [pdf, other]
-
Title: Unitarity in TechnicolorComments: 23 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph)
- [48] arXiv:0811.4638 (replaced) [ps, pdf, other]
-
Title: Hadrons in AdS(5) x S**5Subjects: High Energy Physics - Phenomenology (hep-ph)
- [49] arXiv:0811.4656 (replaced) [ps, pdf, other]
-
Title: Low Energy Constants of Chiral Perturbation Theory from the Instanton VacuumAuthors: M. MusakhanovComments: Talk given at Baldin ISHEPP XIX, Dubna, September 29 - October 4, 2008. Few typos was correctedSubjects: High Energy Physics - Phenomenology (hep-ph)
[ showing up to 2000 entries per page: fewer | more ]