On the two-loop corrections to the Higgs masses in the NMSSM

We discuss the impact of the two-loop corrections to the Higgs mass in the NMSSM beyond $O(\alpha_S(\alpha_b + \alpha_t))$. For this purpose we use the combination of the public tools SARAH and SPheno to include all contributions stemming from superpotential parameters. We show that the corrections in the case of a heavy singlet are often MSSM-like and reduce the predicted mass of the SM-like state by about 1 GeV as long as $\lambda$ is moderately large. For larger values of $\lambda$ the additional corrections can increase the SM-like Higgs mass. If a light singlet is present the additional corrections become more important even for smaller values of $\lambda$ and can even dominate the ones involving the strong interaction. In this context we point out that important effects are not reproduced quantitatively when only including $O((\alpha_b+\alpha_t+\alpha_\tau)^2)$ corrections known from the MSSM.Comment: 23 pages, 11 figure

The Higgs Mass in the MSSM at two-loop order beyond minimal flavour violation

Soft supersymmetry-breaking terms provide a wealth of new potential sources of flavour violation, which are tightly constrained by precision experiments. This has posed a challenge to construct flavour models which both explain the structure of the Standard Model Yukawa couplings and also predict soft-breaking patterns that are compatible with these constraints. While such models have been studied in great detail, the impact of flavour violating soft terms on the Higgs mass at the two-loop level has been assumed to be small or negligible. In this letter, we show that large flavour violation in the up-squark sector can give a positive or negative mass shift to the SM-like Higgs of several GeV, without being in conflict with other observations. We investigate in which regions of the parameter space these effects can be expected.Comment: 8 pages, 9 figure

Gyrokinetic and kinetic particle-in-cell simulations of guide-field reconnection. I: Macroscopic effects of the electron flows

In this work, we compare gyrokinetic (GK) and fully kinetic Particle-in-Cell (PIC) simulations of magnetic reconnection in the limit of strong guide field. In particular, we analyze the limits of applicability of the GK plasma model compared to a fully kinetic description of force free current sheets for finite guide fields ($b_g$). Here we report the first part of an extended comparison, focusing on the macroscopic effects of the electron flows. For a low beta plasma ($\beta_i=0.01$), it is shown that both plasma models develop magnetic reconnection with similar features in the secondary magnetic islands if a sufficiently high guide field ($b_g\gtrsim 30$) is imposed in the kinetic PIC simulations. Outside of these regions, in the separatrices close to the X points, the convergence between both plasma descriptions is less restrictive ($b_g\gtrsim 5$). Kinetic PIC simulations using guide fields $b_g \lesssim 30$ reveal secondary magnetic islands with a core magnetic field and less energetic flows inside of them in comparison to the GK or kinetic PIC runs with stronger guide fields. We find that these processes are mostly due to an initial shear flow absent in the GK initialization and negligible in the kinetic PIC high guide field regime, in addition to fast outflows on the order of the ion thermal speed that violate the GK ordering. Since secondary magnetic islands appear after the reconnection peak time, a kinetic PIC/GK comparison is more accurate in the linear phase of magnetic reconnection. For a high beta plasma ($\beta_i=1.0$) where reconnection rates and fluctuations levels are reduced, similar processes happen in the secondary magnetic islands in the fully kinetic description, but requiring much lower guide fields ($b_g\lesssim 3$).Comment: 18 pages, 13 figures. Revised to match with the published version in Physics of Plasma

Heavy Hyperon--Antihyperon Production

Based on the experience from the production of anti-Lambda Lambda and anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi and anti-Omega Omega in view of: (1) the production dynamics of the heavier antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the (3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson production, where both systems have similar masses (3.345 and 3.057, respectively) and identical valence quark content. A systematic study of the antihyperon--hyperon production with increasing strangeness content is interesting for the following reasons: The anti-Omega Omega production is the creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles. Results of the PS185 experiments prove a clear dominance of the spin triplet anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all in spin triplet configurations when created out of the gluonic interaction they should have spin parity quantum number as 3^- as long as Omega anti-Omega is created with relative L=0 angular momentum. The comparison of the Omega anti-Omega baryon pair to the phi phi phi three meson production (where the three anti-s s quark pairs might not but can be produced without relative correlation) would provide a unique determination of the intermediate matter state. Measurements of excitation functions and polarization transfers should be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p --> phi phi phi reaction channels. Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI.Comment: 4 pages, 2 figures, Presented at LEAP05: International Conference on Low Energy Antiproton Physics, Bonn - Juelich, Germany, May 16-22, 200

Preparation and decay of a single quantum of vibration at ambient conditions

A single quantum of excitation of a mechanical oscillator is a textbook example of the principles of quantum physics. Mechanical oscillators, despite their pervasive presence in nature and modern technology, do not generically exist in an excited Fock state. In the past few years, careful isolation of GHz-frequency nano-scale oscillators has allowed experimenters to prepare such states at milli-Kelvin temperatures. These developments illustrate the tension between the basic predictions of quantum mechanics that should apply to all mechanical oscillators existing even at ambient conditions, and the complex experiments in extreme conditions required to observe those predictions. We resolve the tension by creating a single Fock state of a vibration mode of a crystal at room temperature using a technique that can be applied to any Raman-active system. After exciting a bulk diamond with a femtosecond laser pulse and detecting a Stokes-shifted photon, the 40~THz Raman-active internal vibrational mode is prepared in the Fock state $|1>$ with $98.5\%$ probability. The vibrational state is read out by a subsequent pulse, which when subjected to a Hanbury-Brown-Twiss intensity correlation measurement reveals the sub-Poisson number statistics of the vibrational mode. By controlling the delay between the two pulses we are able to witness the decay of the vibrational Fock state over its $3.9$ ps lifetime at room temperature. Our technique is agnostic to specific selection rules, and should thus be applicable to any Raman-active medium, opening a new generic approach to the experimental study of quantum effects related to vibrational degrees of freedom in molecules and solid-state systems

The relationship between two flavors of oblivious transfer at the quantum level

Though all-or-nothing oblivious transfer and one-out-of-two oblivious transfer are equivalent in classical cryptography, we here show that due to the nature of quantum cryptography, a protocol built upon secure quantum all-or-nothing oblivious transfer cannot satisfy the rigorous definition of quantum one-out-of-two oblivious transfer.Comment: 4 pages, no figur

C II abundances in early-type stars: solution to a notorious non-LTE problem

We address a long-standing discrepancy between non-LTE analyses of the prominent C II 4267 and 6578/82 A multiplets in early-type stars. A comprehensive non-LTE model atom of C II is constructed based on critically selected atomic data. This model atom is used for an abundance study of six apparently slow-rotating main-sequence and giant early B-type stars. High-resolution and high-S/N spectra allow us to derive highly consistent abundances not only from the classical features but also from up to 18 further C II lines in the visual - including two so far unreported emission features equally well reproduced in non-LTE. These results require the stellar atmospheric parameters to be determined with care. A homogeneous (slightly) sub-solar present-day carbon abundance from young stars in the solar vicinity (in associations and in the field) of log C/H +12= 8.29+/-0.03 is indicated.Comment: 8 pages, 5 figure