In the Standard Model, the three charged lepton are identical copies of each other, apart from mass differences. Experimental tests of this feature in rare and semileptonic decays of b hadrons are highly sensitive to New Physics particles which preferentially couple to the 3rd generation. This talk will review the latest lepton universality tests published by the LHCb collaboration..
Charmless B hadron decays are suppressed in the Standard Model and, consequently, very sensitive to potential New Physics contributions. Precision measurements of CP-violation in those decays allow to detect the anomalies. The GAES group has focused on the study of B -> vector vector decays, whose complicated spin structure require sophisticated angular analyses to disentangle the contributing polarisation amplitudes.
This talk summarises Santiago's group activity in this line, focusing on some of the last analyses performed. In particular, the World's first measurement of the CP-violating phase phi_s^dd using Bs->(K+pi-)(K-pi+) decays is presented.
I will present the main lines of activity in research line on Hot and dense QCD in the LHC era and beyond, and show some recent results. I will then discuss the structure of the group and the tentative plans for the future.
We summarize with new insights and explanations our recent contributions [1] to the problem of strong interactions at scales beyond the attomic (10−18m) where QCD enters a nonperturbative regime, based on our generalized integrability approach [2]. It extends the exact methods of integrability and soliton theory in 2 dimensions to the physical 4 dimensions for relativistic effective fields relevant for QCD at large distances (light quark hadrons as nucleons and nuclei) and high densities ( nuclear matter and neutron stars). Specifically, we deal with the deep mesonic theory introduced in the sixties by Skyrme, where the nucleonic charge has a simple geometrical and topological origin. The elusive exact topological stability (BPS saturation ) and the related solvability was achieved in an extension of the model with natural physical motivation (vector meson exchange) and new symmetries (volume preserving diffeomorphisims) [3]. Equipped with exact solutions at the classical level, which explained the saturation of nuclear forces, we performed the semiclassical quantization to reproduce the nuclear spectra of medium and heavy nuclei (light ones require the old Skyrme model contribution). The simplicity of the equations also allows for solving the complete coupling to General Relativity, with back reaction, providing a simple semianalitical explanation of neutron stars, with exact equations of state. This opens the possibility for new phenomenology, and in fact the predictions for masses and compactness (larger than the current nuclear mean field approximations) are in line with the first of the many forthcoming new observations.
References
[1] C. Adam, C. Naya, J. Sanchez-Guillen, R. Vazquez, A. Wereszczynski
A BPS Skyrme model and Nuclear binding energies Phys. Rev.Lett 111, 232501 (2013).
BPS Skyrmions as neutron stars Phys. Lett. B 742 (2015) 136.
The Skyrme model in the BPS limit World Scientific, Singapore 2016.
[2] O. Alvarez, L. Ferreira, J. Sanchez-Guillen. Integrable theory and loop spaces: fundamentals, applications and new developments Int.Journal of Mod.Phys. A 24, 1825-1888 (2009)
[3] C. Adam, J. Sanchez-Guillen, A. Wereszczynski Skyrme-type proposal for baryonic matter
Physics Letters B 691 (2010).
Jet quenching has long been considered one of the key measurements to prove the formation of a quark-gluon plasma in heavy ion collisions. Hard partons created in the early stages must travers the medium created in the collision, losing energy as they interact with strong color fields, yielding to a suppression in the high pt spectrum as compared to an incoherent sum of proton-proton collisions. New developments at LHC and RHIC have allowed us to move from single particle measurements to reconstructed jets, creating a demand for new tools that would allow us to understand how jets, as multi-particle objects, interact with the medium and how their modification can provide information about the properties of the medium. In this talk I will focus in the role played by color coherence in calculating the energy loss and inner modification of jets.
Ever since the discovery of the quark-gluon plasma the understanding of its fast thermalization has been a topic of intense research. We use the gauge/gravity duality to model the out-of-equilibrium first stage of a heavy ion collision through the collision of gravitational shockwaves in numerical relativity. This investigation of collisions of sheets of energy density in a non-conformal theory with a gravity dual is the first non-conformal holographic simulation of a heavy ion collision. We demonstrate new non-conformal physics that arises (as compared to the much simpler conformal case) such as a new plasma relaxation channel, the equilibration of the conformal symmetry breaking scalar condensate and the presence of a sizeable bulk viscosity. These ingredients are crucial to make contact of the fast hydrodynamization process of hot plasmas with real-world QCD deconfinement matter.
We construct a black hole geometry generated by the intersection of Nc color D3- branes and Nf flavor D5-branes along a 2+1 dimensional subspace. Working in the Veneziano limit in which Nf is large and distributing homogeneously the D5-branes in the internal space, we calculate the solution of the equations of motion of supergravity plus sources which includes the backreaction of the flavor branes. The solution is analytic and dual to a 2+1 dimensional defect in a 3+1 dimensional gauge theory, with Nf massless hypermultiplets living in the defect. We study the thermodynamics of the resulting spatially anisotropic geometry and compute the first and second order transport coefficients for perturbations propagating along the defect.
I will talk about the dynamics of a scalar field in Anti-de Sitter spacetime in the presence of a time-periodic source. Through the AdS/CFT correspondence it describes the dynamics of a strongly coupled finite-size quantum system under a homogeneous periodic driving
The Pierre Auger Observatory is shedding light onto the long-standing mysteries of the nature and origin of the highest energy particles produced in the Universe . We present the current status and the latest highlights. We also discuss the prospects for the future in the field of the Ultra High Energy Cosmic Rays.
Trasgos are new generation tracking detectors suitable for cosmic rays studies. The present status of the Trasgo project and all the associated initiatives will be reported.
Status of the present activities and presentation of future plans in rare event searches with neutrinos
Historically, gaseous detectors have represented the paradigmatic tool for the study of rare physics interactions. Modern developments aimed at precision physics in the Neutrino, Nuclear and Dark Matter sector here at IGFAE are detailed in this talk, serving as a brief introduction to some
of the modern descendants of the old cloud chamber: the Optical Time Projection Chamber.
Last minute: Gaseous detectors are unrivaled in large areas as well, when aimed at precise time-of-flight measurements.
The existing world record (20ps) has been recently equaled with a new disruptive technique, and is summarized in this
presentation as well.
https://arxiv.org/abs/1712.05256
Collisions induced by relativistic radioactive ion beams make it possible to create in the laboratory matter with similar characteristics to the one expected to constitute neutron stars, or the matter created during binary neutron star mergers. Researchers from the Experimental Groups of Particle and Nuclei participate in the construction of the R3B experiment at FAIR, and lead some of the physics runs aiming at studying neutron star matter
Understanding nuclear structure and dynamics from the underlying strong force described by QCD is one of the major challenges in nuclear physics today. Exotic nuclei, with extreme ratios of proton-to-neutron number, provide an extreme test for theoretical models of nuclear structure. In this talk I will focus on our present and future experimental studies of exotic matter at the limits of stability
Since its discovery, nuclear fission was understood as a complex and intricate phenomenon where macroscopic and microscopic degrees of freedom compete to drive the process. In a recent campaign, we were able to address this competition from the experimental point of view, gathering new observables that allow a direct comparison with nuclear models, shedding a new light on the role of shell effects on the fission process
CALIFA is a calorimeter intended for the high-efficiency detection of gammas and light charged particles produced in secondary reactions at the R3B target. A large resolution both in the individual gamma energy as well as the total energy (up to tens of MeV) is requested. Protons (up to 300 MeV) produced in the target region crossing the crystal bulk should also be detected with good energy resolution. The main properties of this device, high efficiency and good angular resolution, are imposed by the very particular kinematics of energetic gamma rays emitted by sources moving with relativistic velocities and by the typically low intensities of the secondary beams involved.
Symmetry energy remains as one of the poorly known ingredients of the equation of state (EOS) of nuclear matter. Recent studies showed the correlation between the relative abundance of protons and neutrons at the periphery in nuclei far from the stability and the symmetry energy. To constraint the description of the symmetry energy we performed an experiment at the GSI facility in Darmstadt (Germany) where we measured total interaction, and neutron and proton knockout cross sections of medium-mass nuclei over a broad range of neutron excess
Laser Laboratory for acceleration and applications (L2A2) is a recent infrastructure built at USC, aiming to develop new acceleration technologies based on laser-plasma acceleration. In this talk we will present the status of the laboratory and the different research programs under development
We present the development of an ultrafast X-ray source for high quality imaging, recently installed at the L2A2. This micron size X-ray source is based on the laser plasma interaction, and it makes use of the low energy beam of the laser (1 mJ, 35 fs, 1 kHz). Typical spectra of this source are composed by characteristic peaks of the material used as target and a Bremsstrahlung continuum.