arXiv subjects

A. Pukhov

Publications and source records attributed to A. Pukhov.

At least 109 records · Page 6Linked to original sources

arXiv2008

Dark matter direct detection rate in a generic model with micrOMEGAs2.2

We present a new module of the micrOMEGAs package for the calculation of WIMP-nuclei elastic scattering cross sections relevant for the direct detection of dark matter through its interaction with nuclei in a large detector. With this new module, the computation of the direct detection rate is performed automatically for a generic model of new physics which contains a WIMP candidate. This model needs to be implemented within micrOMEGAs2.1.

hep-ph↗

arXiv2008

Precision measurements, dark matter direct detection and LHC Higgs searches in a constrained NMSSM

We reexamine the constrained version of the Next-to-Minimal Supersymmetric Standard Model with semi universal parameters at the GUT scale (CNMSSM). We include constraints from collider searches for Higgs and SUSY particles, upper bound on the relic density of dark matter, measurements of the muon anomalous magnetic moment and of B-physics observables as well as direct searches for dark matter. We then study the prospects for direct detection of dark matter in large scale detectors and comment on the prospects for discovery of heavy Higgs states at the LHC.

hep-ph↗

arXiv2008

Discriminating dark matter candidates using direct detection

We examine the predictions for both the spin dependent and spin independent direct detection rates in a variety of new particle physics models with dark matter candidates. We show that a determination of both spin independent and spin dependent amplitudes on protons and neutrons can in principle discriminate different candidates of dark matter up to a few ambiguities. We emphasize the importance of making measurements with different spin dependent sensitive detector materials and the need for significant improvement of the detector sensitivities. Scenarii where exchange of new coloured particles contributes significantly to the elastic scattering cross sections are often the most difficult to identify, the LHC should give an indication whether such scenarii are relevant for direct detection.

hep-ph↗

arXiv2008

Technicolor Walks at the LHC

We analyze the potential of the Large Hadron Collider (LHC) to observe signatures of phenomenologically viable Walking Technicolor models. We study and compare the Drell-Yan (DY) and Vector Boson Fusion (VBF) mechanisms for the production of composite heavy vectors. We find that the heavy vectors are most easily produced and detected via the DY processes. The composite Higgs phenomenology is also studied. If Technicolor walks at the LHC its footprints will be visible and our analysis will help uncovering them.

hep-ph↗

arXiv2008

Neutralino relic density from ILC measurements in the CPV MSSM

We discuss ILC measurements for a specific MSSM scenario with CP phases, where the lightest neutralino is a good candidate for dark matter, annihilating efficiently through t-channel exchange of light staus. These prospective (CP-even) ILC measurements are then used to fit the underlying model parameters. A collider prediction of the relic density of the neutralino from this fit gives 0.116<Omega h^2<0.19 at 95% CL. CP-odd observables, while being a direct signal of CP violation, do not help in further constraining Omega h^2. The interplay with (in)direct detection of dark matter and with measurements of electric dipole moments is also discussed. Finally we comment on collider measurements at higher energies for refining the prediction of Omega h^2.

hep-ph↗

arXiv2008

New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 -- New Physics Working Group

We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high pT leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the "New Physics'' working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 11-29 June, 2007).

hep-ph↗

arXiv2008

Collider aspects of flavour physics at high Q

This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.

hep-ph↗

arXiv2007

A Les Houches Interface for BSM Generators

We propose to combine and slightly extend two existing "Les Houches Accords" to provide a simple generic interface between beyond-the-standard-model parton-level and event-level generators. All relevant information - particle content, quantum numbers of new states, masses, cross sections, parton-level events, etc - is collected in one single file, which adheres to the Les Houches Event File (LHEF) standard.

hep-ph↗

arXiv2007

Dark Matter in a Constrained NMSSM

We explore the parameter space of a Constrained Next-to-Minimal Supersymmetric Standard Model with GUT scale boundary conditions (CNMSSM) and find regions where the relic density of the lightest neutralino is compatible with the WMAP measurement. We emphasize differences with the MSSM: cases where annihilation of the LSP occurs via a Higgs resonance at low values of tanβand cases where the LSP has a large singlino component. The particle spectrum as well as theoretical and collider constraints are calculated with NMSSMTools. All neutralino annihilation and coannihilation processes are then computed with micrOMEGAs, taking into account higher order corrections to the Higgs sector.

hep-ph↗

arXiv2007

Control of laser wake field acceleration by plasma density profile

We show that both the maximum energy gain and the accelerated beam quality can be efficiently controlled by the plasma density profile. Choosing a proper density gradient one can uplift the dephasing limitation. When a periodic wake field is exploited, the phase synchronism between the bunch of relativistic particles and the plasma wave can be maintained over extended distances due to the plasma density gradient. Putting electrons into the $n-$th wake period behind the driving laser pulse, the maximum energy gain is increased by the factor $2πn$ over that in the case of uniform plasma. The acceleration is limited then by laser depletion rather than by dephasing. Further, we show that the natural energy spread of the particle bunch acquired at the acceleration stage can be effectively removed by a matched deceleration stage, where a larger plasma density is used.

physics.plasm-ph↗

arXiv2007

Radiative Losses in Plasma Accelerators

We investigate the dynamics of a relativistic electron in a strongly nonlinear plasma wave in terms of classical mechanics by taking into account the action of the radiative reaction force. The two limiting cases are considered. In the first case where the energy of the accelerated electrons is low, the electron makes many betatron oscillations during the acceleration. In the second case where the energy of the accelerated electrons is high, the betatron oscillation period is longer than the electron residence time in the accelerating phase. We show that the force of radiative friction can severely limit the rate of electron acceleration in a plasma accelerator.

physics.acc-ph↗

arXiv2006

Neutralino dark matter in the MSSM with CP violation

In the MSSM, the presence of CP phases can have a significant impact on the neutralino relic abundance. These phase effectsare on the one hand due to shifts in the masses, on the other hand due to modifications of the couplings. Typical variations in Omega h^2 solely from modifications in the couplings are of order 10%-100%.

hep-ph↗

arXiv2006

micrOMEGAs2.0: a program to calculate the relic density of dark matter in a generic model

micrOMEGAs2.0 is a code which calculates the relic density of a stable massive particle in an arbitrary model. The underlying assumption is that there is a conservation law like R-parity in supersymmetry which guarantees the stability of the lightest odd particle. The new physics model must be incorporated in the notation of CalcHEP, a package for the automatic generation of squared matrix elements. Once this is done, all annihilation and coannihilation channels are included automatically in any model. Cross-sections at $v=0$, relevant for indirect detection of dark matter, are also computed automatically. The package includes three sample models: the minimal supersymmetric standard model (MSSM), the MSSM with complex phases and the NMSSM. Extension to other models, including non supersymmetric models, is described.

hep-ph↗

arXiv2006

Theory of high harmonic generation in relativistic laser interaction with overdense plasma

High harmonic generation due to the interaction of a short ultra relativistic laser pulse with overdense plasma is studied analytically and numerically. On the basis of the ultra relativistic similarity theory we show that the high harmonic spectrum is universal, i.e. it does not depend on the interaction details. The spectrum includes the power law part $I_n\propto n^{-8/3}$ for $n<\sqrt{8α}γ_{\max}^3$, followed by exponential decay. Here $γ_{\max}$ is the largest relativistic $γ$-factor of the plasma surface and $α$ is the second derivative of the surface velocity at this moment. The high harmonic cutoff at $\propto γ_{\max}^3$ is parametrically larger than the $4 γ_{\max}^2$ predicted by the ``oscillating mirror'' model based on the Doppler effect. The cornerstone of our theory is the new physical phenomenon: spikes in the relativistic $γ$-factor of the plasma surface. These spikes define the high harmonic spectrum and lead to attosecond pulses in the reflected radiation.

physics.plasm-ph↗

arXiv2006

Relic density of neutralino dark matter in the MSSM with CP violation

We calculate the relic density of dark matter in the MSSM with CP violation. We analyse various scenarios of neutralino annihilation: the cases of a bino, bino-wino and bino-Higgsino LSP, annihilation through Higgs, as well as sfermion coannihilation scenarios. Large phase effects are found, on the one hand due to shifts in the masses, on the other hand due to modifications of the couplings. Taking special care to disentangle the effects in masses and couplings, we demonstrate that the presence of CP phases can have a significant influence on the neutralino relic abundance. Typical variations in Ωh^2 solely from modifications in the couplings are O(10%-100%), but can reach an order of magnitude in some cases.

hep-ph↗

arXiv2006

Les Houches "Physics at TeV Colliders 2005'' Beyond the Standard Model working group: summary report

The work contained herein constitutes a report of the "Beyond the Standard Model'' working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.

hep-ph↗

arXiv2006

Relativistic plasma control for single attosecond pulse generation

To describe the high harmonic generation at plasma surfaces in the relativistic regime, we introduce the concept of {\it apparent reflection point} (ARP). It appears to an external observer that the radiation electric field is zero at the ARP. The relativistic dynamics of the ARP completely defines the generation of high harmonics and attosecond pulses. The ARP velocity is a smooth function of time. The corresponding $γ$-factor, however, has sharp spikes at the times when the tangential vector potential vanishes and the surface velocity becomes close to the speed of light. We show that managing the laser polarization, one can efficiently control the ARP dynamics, e.g., to gate a single (sub-)attosecond pulse out of the short pulse train generated by a multi-cycle driver. This relativistic control is demonstrated numerically by particle-in-cell simulations.

physics.plasm-ph↗

arXiv2005

Focusing of laser-generated ion beams by a plasma cylinder: similarity theory and the thick lens formula

It is shown that plasma-based optics can be used to guide and focus highly divergent laser-generated ion beams. A hollow cylinder is considered, which initially contains a hot electron population. Plasma streaming toward the cylinder axis maintains a focusing electrostatic field due to the positive radial pressure gradient. The cylinder works as thick lens, whose parameters are obtained from similarity theory for freely expanding plasma in cylindrical geometry. Because the lens parameters are energy dependent, the lens focuses a selected energy range of ions and works as a monochromator. Because the focusing is due to the quasineutral part of the expanding plasma, the lens parameters depend on the hot electron temperature $T_e$ only, and not their density.

physics.plasm-ph↗