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The charm and beauty of the Little Bang

In relativistic heavy-ion collisions a “Little-Bang” is produced, in which the matter for a few fm/c experiences very similar (but not equal) conditions to the one occurred in the early universe, about one millionth of a second after the Big Bang. In particular one expects to produce a fireball of deconfined QCD matter in which the active degrees of freedom are quarks and gluons rather than hadrons. If this fireball lives for such a short amount of time, which are the experimental signatures of the onset of deconfinement and how can one extract information about its properties from the experimental data? In this connection I will show how heavy-flavour particles arising from the hadronization of charm and beauty quarks play a major role.

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Multiplicity and energy dependence of light charged particle production in ALICE at the LHC

ALICE (A Large Ion Collider Experiment) is the CERN LHC experiment optimized for the study of the strongly interacting matter produced in heavy-ion collisions and for the characterization of the quark-gluon plasma (QGP). ALICE has collected precision data at different energies for pp, p-Pb, Pb-Pb and Xe-Xe collisions: this unique set of data allows us to investigate bulk particle production for very different systems and compare them at similar multiplicities. In particular, light flavour particles, containing only u, d and s valence quarks, are the most copiusly produced and so they play a central role in the characterization of the bulk properties of the QGP, carrying essential information about the produced medium and reaction dynamics. Part of this information is carried by the inclusive and identified transverse momentum distributions of light charged particles, measured over a wide pT range thanks to the excellent tracking and particle-identification capabilities of the ALICE detector. Such distributions show that at low to intermediate pT charged particle production is governed by the collective expansion of the system. The chemical and kinetic freeze-out parameters of the system are extracted via statistical-thermal and combined blast-wave fits to the data in heavy-ion collisions and are compared to results obtained in pp and p-Pb collisions at similar multiplicities. At high pT, typically above 5 GeV/c, a suppression of hadronic production, due to medium effects such as parton energy loss, can be observed. These effects can be investigated by calculating the nuclear modification factor, defined as the ratio between the pT spectrum measured in nucleus-nucleus collisions and a reference spectrum in pp collisions scaled by the number of binary nucleon-nucleon collisions. In this talk, we review the most recent ALICE results on the production of pions, ...

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From kaonic atoms to strangeness in neutron stars

An updated review is presented of the theory of low-energy antikaon and hyperon interactions with nucleons and nuclear systems. Applications include kaonic hydrogen, recent calculations of kaonic deuterium and comparisons with K-p correlation functions from ALICE at LHC. This is followed by a discussion of the possible role played by kaons and hyperons in dense baryonic matter, with special emphasis on constraints provided by the existence of two-solar-mass neutron stars and garvitational wave signals of neutron star mergers.

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The ILC project – its physics and status

The international Linear Collider (ILC) is an electron-positron collider whose initial goal is to make precision measurements on the Higgs boson. Such measurements are expected to elucidate the shortcomings of the Standard Model of elementary particles and guide us to the new physics that governs the universe. Being a linear collider, It also has potential to upgrade its collision energy without sacrificing the investment up to that point.  In this talk, we review the scientific case of the ILC and describe its political status.

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MariX: Conceptual Design Report of a Multi-disciplinary Advanced Research Infrastructure for the generation and application of X-rays

The need of a fs-scale pulsed, MHz-class repetition rate, X-ray source for time-resolved fine analysis of matter (spectroscopy and photon scattering) in the linear response regime is addressed by the conceptual design of a facility called MariX, outperforming current X-ray sources based on FELs or Synchrotrons for the declared scope. MariX is based on the original design of a two-pass two-way superconducting linear electron accelerator, equipped with an arc compressor, to be operated in CW mode with up to 1MHz repetition rate. MariX provides FEL emission in the range 0.2-8 keV with up to 10^10 photons per pulse and up to 10^16 photons/s using a 1.5 GeV Linac, but delivering to the FEL undulators up to 3.8 GeV electrons. The accelerator complex includes an early stage that supports an advanced inverse Compton source of very high-flux hard X-rays (up to 10^13 monochromatic X-ray photon beams), of energies up to 180 keV, that are well adapted for large area advanced radiological imaging. Such a complex enables a broad science program and will serve a multidisciplinary user community, covering fundamental science of matter and application to life sciences, including health at preclinical and clinical level. MariX C.D.R. has been recently published on its dedicated web site: www.marix.eu.

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B-decay discrepancies: Where we stand after Moriond 2019

A whole set of B-decay data display persistent deviations with respect to the Standard Model (SM). Specifically, data hint at new effects in semi-leptonic interactions involving the b -> s and b -> c currents. Interestingly, the pattern of discrepancies after the recent Run-2 updates suggest well-defined effective-field theory (EFT) scenarios where the two sets of discrepancies, b -> s and b -> c, are related. In turn, such EFT picture finds a quantitative realization within well-defined UV-complete scenarios. I will provide a review of the whole subject, from data to the EFT picture to UV models.  

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Quantum Optical Control of Levitated Solids: a novel probe for the gravity-quantum interface

The increasing level of control over motional quantum states of massive, solid-state mechanical devices opens the door to an hitherto unexplored parameter regime of macroscopic quantum physics. I will report on our recent progress towards controlling levitated solids in the quantum regime. I will discuss the prospects of using these systems for fundamental tests of physics, including the interface between quantum and gravitational physics.

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Global fits to b → cτν transitions

We perform a general model-independent analysis of b → cτντ transitions, including measurements of RD , RD∗ , their q2 differential distributions, the recently measured longitudinal D∗ polarization FD∗, and constraints from the Bc → τντ lifetime, each L of which has significant impact on the fit. A global fit to a general set of Wilson coefficients of an effective low-energy Hamiltonian is presented, the solutions of which are interpreted in terms of hypothetical new-physics mediators. From the obtained results we predict selected b → cτντ observables, such as the baryonic transition Λb → Λcτντ, the ratio RJ/ψ, the forward-backward asymmetries AD(∗), FB the τ polarization asymmetries PD(∗) , and the longitudinal D∗ polarization fraction τ F D∗ . The latter shows presently a slight tension with any new-physics model, such L that an improved measurement could have an important impact.  

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Some new ideas in Leptogenesis and Dark Matter studies

Type-1 seesaw is the simplest extension of the Standard Model (SM) that explains light neutrino masses and baryon asymmetry of the universe (BAU) via leptogenesis. In the first part of this talk, I shall discuss how different seesaw models can be visualised graphically and how a fine-tuning in the seesaw formula can be related to a Lorentz boost in the flavour space. I shall discuss a new parametrization of standard Casas-Ibarra orthogonal matrix and show how this new parametrisation is more useful in leptogenesis studies, particularly in SO (10) models. In the second part, I will show that an additional right handed (RH) neutrino could be a DM candidate in the two RH neutrino seesaw model if one considers the new one interacts with the other two with an effective dimension 5 operator induced by SM Higgs. This operator creates a temperature dependent matter potential and therefore the DM (the new RH neutrino) is produced from RH neutrino oscillation due to MSW-like matter effect even if the scale of new physics is post-Planckian. The operator responsible for DM production also causes the DM decay (to light neutrinos) and makes the scenario testable at neutrino telescopes such as IceCube.

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