Search for Supersymmetric Dark Matter with Superfluid He3 (MACHe3)

MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter search, using superfluid He3 as a sensitive medium. This paper presents a phenomenological study done with the DarkSUSY code, in order to investigate the discovery potential of this project of detector, as well as its complementarity with existing and planned devices.Comment: 15 pages, 5 figures, submitted to Phys. Letters B, minor changes in the tex

Two photon annihilation of Kaluza-Klein dark matter

We investigate the fermionic one-loop cross section for the two photon annihilation of Kaluza-Klein (KK) dark matter particles in a model of universal extra dimensions (UED). This process gives a nearly mono-energetic gamma-ray line with energy equal to the KK dark matter particle mass. We find that the cross section is large enough that if a continuum signature is detected, the energy distribution of gamma-rays should end at the particle mass with a peak that is visible for an energy resolution of the detector at the percent level. This would give an unmistakable signature of a dark matter origin of the gamma-rays, and a unique determination of the dark matter particle mass, which in the case studied should be around 800 GeV. Unlike the situation for supersymmetric models where the two-gamma peak may or may not be visible depending on parameters, this feature seems to be quite robust in UED models, and should be similar in other models where annihilation into fermions is not helicity suppressed. The observability of the signal still depends on largely unknown astrophysical parameters related to the structure of the dark matter halo. If the dark matter near the galactic center is adiabatically contracted by the central star cluster, or if the dark matter halo has substructure surviving tidal effects, prospects for detection look promising.Comment: 17 pages, 3 figures; slightly revised versio

Managers' and employees' experiences of how managers' wellbeing impacts their leadership behaviours in Swedish small businesses

BACKGROUND: There is a growing interest in managers' wellbeing due to the observed associations between their wellbeing and leadership behaviours, and between leadership behaviours and employees' wellbeing. However, it is still unclear how managers' wellbeing influences their practiced leadership across different workplace contexts, which specific behaviours are affected, and how this varies across time. OBJECTIVE: The purpose of this study was therefore to explore managers' and employees' experiences and perceptions regarding the consequences of managers' wellbeing for their leadership behaviours in small businesses. METHODS: Semi-structured interviews were conducted with 39 participants (20 managers and 19 employees) working at 12 Swedish small firms, and analysed using content analysis. RESULTS: The findings showthat managers were more constructive when they felt well, and more passively destructive when unwell. Variations in managers' wellbeing influenced their mood, energy level, and performance, as well as the company's working climate. However, these destructive leadership variations did not have a substantial impact, because several protective factors were present. CONCLUSION: This study shows that the wellbeing of managers in small businesses has perceptible consequences for their leadership behaviours. The study also shows that sustained leadership behaviours may coexist with temporary variations of these behaviours on a constructive-destructive continuum depending on the leader's wellbeing. Overall, the findings contribute to a more nuanced and dynamic understanding of how the interaction between managers' wellbeing and their behaviours unfolds in the particular context of small companies

The Photovoltaic Crisis and the Demand-side Generation in Spain

The RES-E promotion policy in Spain gave priority to the photovoltaic (henceforth, PV) ground-mounted installations. For years, the coupling of customer-side generation coupled with excess energy exports was never specifically considered. However, some months ago this option was suggested as a way to recover the Spain��s PV sector from the current moratorium on the RES-E policy. A decree draft on on-site generation was issued, its central point being the consideration of electricity exports as delayed consumption rights. But several barriers hinder its entry into force. Unfortunately, Spain could be losing an important opportunity for encouraging PV investments while retail grid parity is being reached. This working paper analyzes the different types of PV demand-side generation from the point of view of consumer-generators and evaluates the economic and technical features of the regulation proposed in Spain and to date still pending

Constraining dark energy

In this paper we propose a mechanism that protects theories violating a holographic bound suggested in arXiv:1203.5476 from developing accelerated expansion. The mechanism builts on work on transplanckian physics, and a non-trivial choice of vacuum states. If correct, it lends further support for detectable signatures in the CMBR signalling new physics.Comment: 8 pages. arXiv admin note: text overlap with arXiv:astro-ph/0606474. Minor misprints correcte

Gluon fragmentation to ^3D_J quarkonia

We present a calculation of the leading order QCD fragmentation functions for gluons to split into spin-triplet D-wave quarkonia. We apply them to evaluate the gluon fragmentation contributions to inclusive ^3D_J quarkonium production at large transverse momentum processes like the Tevatron and find that the D-wave quarkonia, especially the charmonium 2^{--} state, could be observed through color-octet mechanism with present luminosity. Since there are distinctively large gaps between the contributions of two different (i.e, color-singlet and color-octet) quarkonium production mechanisms, our results may stand as a unique test to NRQCD color-octet quarkonium production mechanism.Comment: 15 pages in LaTex (2 figures in PS-file

J/Psi Production from Electromagnetic Fragmentation in Z decay

The rate for $Z^{0}\to J/ \psi + \ell^{+}\ell^{-}$ is suprisingly large with about one event for every million $Z^{0}$ decays. The reason for this is that there is a fragmentation contribution that is not suppressed by a factor of $M^{2}_{\psi}/M^{2}_{Z}$. In the fragmentation limit $M_{Z}\to\infty$ with $E_{\psi}/M_{Z}$ fixed, the differential decay rate for $Z^{0}\to J/ \psi + \ell^{+}\ell^{-}$ factors into electromagnetic decay rates and universal fragmentation functions. The fragmentation functions for lepton fragmentation and photon fragmentation into $J/\psi$ are calculated to lowest order in $\alpha$. The fragmentation approximation to the rate is shown to match the full calculation for $E_{\psi}$ greater than about $3 M_{\psi}$.Comment: 16 pages and 8 figure