At the eve of the second LHC data taking run, some of the most recent results obtained by the LHCb collaboration with Run I data are reviewed. Improved measurements on CP violation, unitary triangle and mixing parameters are shown. Recent progress on
physics in the forward region is illustrated by examples picked up in the electroweak physics and beyond Standard Model searches.
In this paper we analyze Abelian-Higgs strings in a phenomenological model that takes quantum effects in curved space-time into account. This model, first introduced by Rastall, cannot be derived from an action principle. We formulate phenomenologica
l equations of motion under the guiding principle of minimal possible deformation of the standard equations. We construct string solutions that asymptote to a flat space-time with a deficit angle by solving the set of coupled non-linear ordinary differential equations numerically. Decreasing the Rastall parameter from its Einstein gravity value we find that the deficit angle of the space-time increases and becomes equal to $2pi$ at some critical value of this parameter that depends on the remaining couplings in the model. For smaller values the resulting solutions are supermassive string solutions possessing a singularity at a finite distance from the string core. Assuming the Higgs boson mass to be on the order of the gauge boson mass we find that also in Rastall gravity this happens only when the symmetry breaking scale is on the order of the Planck mass. We also observe that for specific values of the parameters in the model the energy per unit length becomes proportional to the winding number, i.e. the degree of the map $S^1 rightarrow S^1$. Unlike in the BPS limit in Einstein gravity, this is, however, not connect to an underlying mathematical structure, but rather constitutes a would-be-BPS bound.
We describe a method of extrapolation based on a truncated Kramers-Kronig relation for the complex permittivity ($epsilon$) and permeability ($mu$) parameters of a material, based on finite frequency data. Considering a few assumptions, such as the b
ehavior of the loss tangent and the overall nature of corrections, the method is robust within a small relative error, if the assumed hypotheses hold at the extrapolated frequency range.
This work presents a brief and non-technical description of the main results and concepts of the modern scientific cosmology, viewing it from an epistemological perspective which allows a dialog with other modes of thinking like e.g. history, philoso
phy, sociology and religion. This epistemological viewpoint is based on the philosophical theses advanced by Ludwig Boltzmann (1844-1906) which states that scientific theories are nothing more than representations, or images, of nature (arXiv:physics/0701308v1). By being representations one cannot know how nature really is because the intrinsic and indispensable properties that characterize nature are unreachable by science. In other words, the true essences that constitute nature are unknowable. Therefore, all answers proposed by science are partial, simplified and replaceable. Another way of putting forward this viewpoint is to state that all scientific truths are provisional, a result which naturally leads to the conclusion that the same set of phenomena, or scientific questions, may have various answers, or representations. This conclusion is generally known as theoretical pluralism (arXiv:physics/9806011). It is exactly such a plurality for conceiving, or representing, nature that opens the way for a possibly fruitful dialog among the various forms of thinking, since this dialog can take place in the realm of the representations. A few examples taken from cosmology, sociology and theology are discussed in the context of this epistemological framework.
We analyze Hubbles approach to cosmology. In 1929 he accepted a finite expanding universe in order to explain the redshifts of distant galaxies. Later on he turned to an infinite stationary universe due to observational constraints. We show, by quoti
ng his works, that he remained cautiously against the big bang until the end of his life.
We report results of the eclipse mapping analysis of an ensemble of light curves of HT Cas. The fast response of the white dwarf to the increase in mass transfer rate, the expansion rate of the accretion disc at the same time, and the relative amplit
ude of the high-frequency flickering indicate that the quiescent disc of HT Has has high viscosity, alpha ~ 0.3-0.7. This is in marked disagreement with the disc-instability model and implies that the outbursts of HT Cas are caused by bursts of enhanced mass-transfer rate from its donor star.
We report the discovery of a hard-thermal (T ~ 130 MK) and variable X-ray emission from the Be star HD 157832, a new member of the puzzling class of gamma-Cas-like Be/X-ray systems. Recent optical spectroscopy reveals the presence of a large/dense ci
rcumstellar disc seen at intermediate/high inclination. With a B1.5V spectral type, HD 157832 is the coolest gamma-Cas analog known. In addition, its non detection in the ROSAT all-sky survey shows that its average soft X-ray luminosity varied by a factor larger than ~ 3 over a time interval of 14 yr. These two remarkable features, ``low effective temperature and likely high X-ray variability turn HD 157832 into a promising object for understanding the origin of the unusually high temperature X-ray emission in these systems.
Using the solutions of the gap equations of the magnetic-color-flavor-locked (MCFL) phase of paired quark matter in a magnetic field, and taking into consideration the separation between the longitudinal and transverse pressures due to the field-indu
ced breaking of the spatial rotational symmetry, the equation of state (EoS) of the MCFL phase is self-consistently determined. This result is then used to investigate the possibility of absolute stability, which turns out to require a field-dependent bag constant to hold. That is, only if the bag constant varies with the magnetic field, there exists a window in the magnetic field vs. bag constant plane for absolute stability of strange matter. Implications for stellar models of magnetized (self-bound) strange stars and hybrid (MCFL core) stars are calculated and discussed.
Anomalous X-ray Pulsars and Soft-Gamma Repeaters groups are magnetar candidates featuring low characteristic ages ($tau = {Pover{2 {dot P}}}$). At least some of them they should still be associated with the remnants of the explosive events in which t
hey were born, giving clues to the type of events leading to their birth and the physics behind the apparent high value of the magnetar magnetic fields. To explain the high values of $B$, a self-consistent picture of field growth also suggests that energy injection into the SNR is large and unavoidable, in contrast with the evolution of {it conventional} SNR. This modified dynamics, in turn, has important implications for the proposed associations. We show that this scenario yields low ages for the new candidates CXOU J171405.7-381031/CTB 37B and XMMU J173203.3-344518/G353.6-0.7, and predicted values agree with recently found ${dot P}$, giving support to the overall picture.
Stafford proved that every left or right ideal of the Weyl algebra A_n(K) is generated by two elements. In this paper we prove that every left or right ideal of the ring of differential operators over the field of formal Laurent series K((x_1,...,x_n
)) is also generated by two elements. The same is true for the ring of differential operators over the convergent Laurent series C{{x_1,...,x_n}}. This is in accordance with the conjecture that says that in a (noncommutative) noetherian simple ring, every left or right ideal is generated by two elements.
