Revival of the Thermal Sneutrino Dark Matter

The left-handed sneutrino in the Minimal Supersymmetric Standard Model (MSSM) has been ruled out as a viable thermal dark matter candidate, due to conflicting constraints from direct detection experiments and from the measurement of the dark matter relic density. The intrinsic fine-tuning problem of the MSSM, however, motivates an extension with a new U(1)' gauge symmetry. We show that in the U(1)'-extended MSSM the right-handed sneutrino becomes a good thermal dark matter candidate. We identify two generic parameter space regions where the combined constraints from relic density determinations, direct detection and collider searches are all satisfied.Comment: 5 pages, 3 figures. Version to appear in Phys. Rev.

The U(1) symmetry of the non-tribimaximal pattern in the degenerate mass spectrum case of the neutrino mass matrix

On account of the new neutrino oscillation data signalling a non-zero value for the smallest mixing angle ($\theta_z$), we present an explicit realization of the underlying U(1) symmetry characterizing the maximal atmospheric mixing angle ($\theta_y = \pi / 4$) pattern with two degenerate masses but now with generic values of $\theta_z$. We study the effects of the form invariance with respect to U(1), and/or $Z_3$, $Z_2$ subgroups, on the Yukawa couplings and the mass terms. Later on, we specify $\theta_z$ to its experimental best fit value ($\sim 8^o$), and impose the symmetry in an entire model which includes charged leptons, and many Higgs doublets or standard model singlet heavy scalars, to show that it can make room for the charged lepton mass hierarchies. In addition, we show for the non-tribimaximal value of $\theta_z \neq 0$ within type-I seesaw mechanism enhanced with flavor symmetry that neutrino mass hierarchies can be generated. Furthermore, lepton/baryogenesis can be interpreted via type-II seesaw mechanism within a setup meeting the flavor U(1)-symmetry.Comment: latex, 1 table, 20 pages. Typos are corrected, shortened version to appear in Phys. Rev.

Kualitas Pelayanan, Kepuasan, Dan Loyalitas Nasabah: Aplikasi Servqual Model Pada Lembaga Keuangan Mikro Syariah Kota Malang

This study aims at: (i) analyzing the direct effect of service quality on customer satisfaction; (ii) analyzing the direct effect of service quality on customer loyalty (iii ) analyzing the direct effect of customer satisfaction on customer loyalty; (iv) Testing empirically the factors of service quality wich is influential in the process of customer loyalty throught customer satisfaction. This study is a survey research -type explanations. The samples used are 112 respondents as clients of Microfinance Institutions Sharia (LKMS) Malang. Sampling techniques of purposive sampling . Statistical analysis path analysis.The results: (i) quality of service a significant effect on customer satisfaction , while the dimensions of tangibles and empathy has no effect on customer satisfaction and loyalty. (ii) The service quality a significant effect on customer loyalty. (iii) affect customer satisfaction has on an effect customer loyalty. (iv) The quality of the service a significant effect on customer loyalty through customer satisfaction

Cosmological string models from Milne spaces and SL(2,Z) orbifold

The $n+1$-dimensional Milne Universe with extra free directions is used to construct simple FRW cosmological string models in four dimensions, describing expansion in the presence of matter with $p=k \rho$, $k=(4-n)/3n$. We then consider the n=2 case and make SL(2,Z) orbifold identifications. The model is surprisingly related to the null orbifold with an extra reflection generator. The study of the string spectrum involves the theory of harmonic functions in the fundamental domain of SL(2,Z). In particular, from this theory one can deduce a bound for the energy gap and the fact that there are an infinite number of excitations with a finite degeneracy. We discuss the structure of wave functions and give examples of physical winding states becoming light near the singularity.Comment: 14 pages, harvma

Seesaw Right Handed Neutrino as the Sterile Neutrino for LSND

We show that a double seesaw framework for neutrino masses with $\mu-\tau$ exchange symmetry can lead to one of the righthanded seesaw partners of the light neutrinos being massless. This can play the role of a light sterile neutrino, giving a $3+1$ model that explains the LSND results. We get a very economical scheme, which makes it possible to predict the full $4\times 4$ neutrino mass matrix if CP is conserved. Once CP violation is included, effect of the LSND mass range sterile neutrino is to eliminate the lower bound on neutrinoless double beta decay rate which exists for the three neutrino case with inverted mass hierarchy. The same strategy can also be used to generate a natural $3+2$ model for LSND, which is also equally predictive for the CP conserving case in the limit of exact $\mu-\tau$ symmetry.Comment: 13 pages and one figure; model extended to 3+2 cas

Modelling and Experimental Study of Dissimilar Arc Stud Welding of AISI 304L to AISI 316L Stainless Steel

This paper has aimed to try and establish a successful weld joint between AISI 304L stainless steel as a stud and AISI 316L stainless steel as a plate by using an arc stud welding process. The effect of different current and time welding on the torque results was experimentally studied, by using three-level of each process parameter. The post-weld heat treatment (PWHT) was carried out on the optimum sample of torque, to study the effect of PWHT on mechanical properties (torque and hardness) and microstructure of the welding zone. In the present work, A 3-D finite element model was developed by using ANSYS software version 18 to analyze the influence of time and current welding on the temperature distribution and residual stresses of the resultant welded joints. A transient thermal model was built to predict the temperature distribution whereas the residual stresses were determined by using a static structural model. The PWHT has been used to reduce the amount of residual stresses and enhance the mechanical properties of the welded joint. The micro-hardness based on the Vickers test and the microstructure of welded specimens with and without PWHT have been investigated. The simulation results reveal that the generated temperature and the residual stress is strongly affected by the time and current welding. The mechanical test results indicated that the PWHT prompted an improvement in the hardness values

Modelling and Experimental Study of Dissimilar Arc Stud Welding of AISI 304L to AISI 316L Stainless Steel

This paper has aimed to try and establish a successful weld joint between AISI 304L stainless steel as a stud and AISI 316L stainless steel as a plate by using an arc stud welding process. The effect of different current and time welding on the torque results was experimentally studied, by using three-level of each process parameter. The post-weld heat treatment (PWHT) was carried out on the optimum sample of torque, to study the effect of PWHT on mechanical properties (torque and hardness) and microstructure of the welding zone. In the present work, A 3-D finite element model was developed by using ANSYS software version 18 to analyze the influence of time and current welding on the temperature distribution and residual stresses of the resultant welded joints. A transient thermal model was built to predict the temperature distribution whereas the residual stresses were determined by using a static structural model. The PWHT has been used to reduce the amount of residual stresses and enhance the mechanical properties of the welded joint. The micro-hardness based on the Vickers test and the microstructure of welded specimens with and without PWHT have been investigated. The simulation results reveal that the generated temperature and the residual stress is strongly affected by the time and current welding. The mechanical test results indicated that the PWHT prompted an improvement in the hardness values

Preparation of Standard Source as a Petri Dish for Plant by Using 152Eu Element

Observed in the recent period, there is an urgent need to a prepare standard sources can be adopted in the research Iraqi universities and scientific Institutions, whether if these measurements for large sizes samples such as  Marinelli beaker , or small sizes such as a petri dish and the latter was not available as standard sources, which was the purpose of this work to prepare standard source with size of a petri dish for  plants  using 152Eu Isotope , that can be adopted in the experimental measurements.The prepared sample was measured in the first lab ( Department of physics/ college of education for pure science/Ibn Al-Haitham/University of Baghdad) and the second lab (Central Laboratories Directorate / nuclear research center at Tuwaitha) by using Gamma spectroscopy system with a high-purity germanium detector (HPGe). The specific activity of the prepared standard sample was calculated using an efficiency curve , which drawn by using the Monte Carlo Program . The results of the specific activity are equal to (1167.610Bq/kg) in first lab and (1081.94 Bq/kg) in second lab. It was noted there is good agreement between the results in the first and second lab, so the overall average of the specific activity adopted  was equal to (1124.7 Bq / kg)From this work, we can use this source to calculate the radioactivity for other radionuclide in small samples (plants), which is difficult to obtained in large quantities, through a calibration  spectrum for efficiency and energy of this prepared source. Keywords: petri dish, prepare standard source, Gamma spectroscopy, activity, HPGe,  Plant