Tag Archives: Evento scientifico

“Physics behind precision'' at future linear or circular colliders (ILC /FCC projects) require imporved input parameters. I will review the role alpha_{QED, eff} at future collider energies and report on possible progres from low energy machines. Besides "what physics can be discovered" with such FCC-ee option, we also would like to understand better how nature works when energies increase.

The first round of data taking with CMD-3 detector at VEPP-2000 e+e collider (BINP, Novosibirsk, Russia) was performed in 2011-2013. The CMD-3 is the general purpose particle detector, equipped by tracking system, two crystal (CSI and BGO) calorimeters, liquid Xe calorimeter, TOF and muon systems. The main goal of experiments at CMD-3 is the measurement of cross-sections and dynamics of exclusive modes of e+e- —> hadrons. In particular, these results provide important input for calculation of the hadronic contribution to the muons anomalous magnetic moment. Here we present the survey of results of analysis of data taken in 2011-2013, including modes of e+e- —> hadrons with up to 6 pions or 2 kaons in final state. About 60 1/pb were taken in the energy range from 0.32 to 2.0 GeV in c.m. The beam energy was continuously measured concurrently with the data taking using Compton backscattering. In 2016 VEPP-2000 resumed operations after upgrade with project luminosity of 1032cm2s-1 at 2 GeV.  

The use of charged particles and nuclei in cancer therapy (hadrontherapy) is one of the most successful cases of application of nuclear physics to medicine. The physical advantages in terms of precision and selectivity, combined with the biological properties of densely ionizing radiation, make the charged particle approach an elective choice in a number of cases. Hadrontherapy is in continuous development and it is an interdisciplinary field where physicians, biologists and physicists contribute together. Indeed the role of physicists is still very important for the progress of Particle Therapy, and the purpose of this seminar is mainly to discuss those aspects where nuclear and particle physicists are presently active. A particular attention will be devoted to the problem of reducing the uncertainties on particle range. This problem is closely connected with the ability to achieve the promised precision. At present, uncertainties in particle range lead to the employment of safety margins, at the expenses of treatment quality. One of the research items in particle therapy is therefore aimed at developing methods to verify the particle range in patients. Non-invasive in-vivo monitoring of the particle range can be performed by detecting secondary radiation, emitted from the patient as a result of nuclear interactions of charged hadrons with tissue, including β+ emitters, prompt photons, and charged particles. Dedicated detector systems are being developed. The proposed approaches require reliable and precise Monte Carlo predictions and a dedicated research activity for the continuous improvement of existing models is also necessary.

After 100 years from the formulation of the theory of general relativity by Albert Einstein, gravitational waves have been finally observed on September 14, 2015 as a transient signal by the two detectors of the Laser Interferometer Gravitational-Wave Observatory, LIGO. In this mini-workshop the results by LIGO and VIRGO collaborations will be presented, together with a historical review of gravitational wave detectors. Future implications of gravitational waves observation in astrophysics will be also discussed.

We discuss models for inflation in the framework of supergravity. The embedding of the Starobinsky model and the relevance of non-linear representations(nilpotent super fields)to describe De Sitter phases in cosmology are presented.

1) Precision Diboson Observables for the LHC Motivated by the restoration of SU(2)×U(1) at high energy, we suggest that certain ratios of diboson differential cross sections can be used as high-precision observables at the LHC. We rewrite leading-order diboson partonic cross sections in a form that makes their SU(2)×U(1)and custodial SU(2) structure more explicit than in previous literature, and identify important aspects of this structure that survive even in hadronic cross sections. We then focus on higher-order corrections to ratios of γγ, Zγ and ZZ processes, including full next-to-leading-order corrections and gg initial-state contributions, and argue that these ratios can likely be predicted to better than 5%, which should make them useful in searches for new phenomena. The ratio of Zγ to γγ is especially promising in the near term, due to large rates and to exceptional cancellations of QCD-related uncertainties. 2) Photon Jets Photon Jets are beams of collimated photons that may appear as a single (poorly isolated) photon to calorimeters at LHC. Several recent articles suggested that the recent 750 GeV excess at LHC may be explained as pairs of Photon Jets rather than pairs of photons. I will briefly introduce the excess and then proceed to highlight some of the tools that we might find useful to discriminate between photons, neutral pion rich hadronic jets and Photon Jets.

Abstract: Is quantum superpostion an exact principle of nature? Recent progress in technological developments allow to explore the quantum properties of very complex systems, bringing the question of whether also macroscopic systems share such features, within experimental reach. It seems feasible to generate for instance quantum superposition states of particles of mass of one million amu (atomic mass unit) [1]. The interest in such experiments is increased by the fact that, on the theory side, some suggest that the quantum superposition principle is not exact, departures from it being the larger, the more macroscopic the system [2].    We will report on new ideas to experimentally test the superposition principle with non-interferometric methods. Testing the superposition principle intrinsically also means to test suggested extensions of quantum theory. For instance collapse models predict a heating effect, which results in a Brownian-like random motion of any isolated particle in space. The heating can be monitored using optomechanical systems even in the classical regime, if competing sources of heat can be reduced sufficiently. We will emphasise levitated optomechanical systems and discuss the possibility to test the heating effect by detecting the motion of the particle in space [4] as well as in the frequency domain where heating is manifested as increase of the spectral feature [5].   We will show quantitative calculations for experiments in both regimes and compare to the state-of-the-art. We will also report on the status of our experiments on optical levitation and parametric feedback cooling of the 3d motion …

Aim of the workshop: Identifying what Dark Matter (DM) is, as well as its nature and properties, remains a major challenge for both theoretical and experimental astroparticle physics communities. In the past decades, Weakly Interacting Massive Particle (WIMP) DM has been the most hunted candidate, with the result that nowadays WIMPs are cornered by large amounts of experimental data from Direct Detection, Indirect Detection and Collider Experiments. If no WIMP signal is detected in the next few years, the possibility that this very appealing theoretical idea is not what Nature has chosen will become even more compelling and will boost theoretical studies and experimental searches for non-WIMP alternatives for DM. The aim of this 3-day meeting is to convene experts on alternatives to the WIMP paradigm to stimulate informal discussions on different possibilities (dark photons, axion-like particles, Majorons, self-interacting dark sectors, just to mention a few). We plan to have only three or four talks each day and plenty of time to discuss implications of these DM scenarios, experimental search strategies, new theoretical proposals, and out-of-mainstream ideas. The general approach and format of the talks will be pedagogical and aimed at favoring extended discussions among all participants. The audience will range from theorists who are expert on related topics to skillful experimentalists planning new non-WIMP detection experiments, as well as postdocs, graduate students and non-expert colleagues working in different areas. Speakers: J. Beacham (Ohio State U. & CERN) “Lost in a Dark Photon Wood: Searches for hidden light gauge bosons …

Recently astronomical data are accumulated, reporting discoveries of very early formed objects, such as supermassive black holes (quasars), gamma bursters, supernovae, and very bright galaxies at high redshifts. Moreover, there is an evidence to existence of starts in our Galaxy which are too old, even older than the universe. All such objects cannot be created in the frameworks of accepted scenarios of their formation. An origin of supermassive black holes observed in the centers of many (maybe all) large and some small galaxies also remains mysterious. After a review of the observations a model is presented that can explain the unusual features of the data and that, as a by product, predicts abundant cosmological antimatter, in particular almost at hand, in the Galaxy. Though the model may be rather speculative, the observed objects present serious challenge to the theory and possibly indicate that “there is something rotten in the state of the universe”.

This mini-workshop is devoted to collective effects and electron cloud studies in circular accelerators. The investigation and comprehension of collective effects is fundamental for the success of accelerators. In particular the electron cloud instability poses severe limitations to the performances of colliders or damping rings for linear colliders. These topics were deeply studied with great competence and passion by our colleague Theo Demma, who passed away a year ago. Theo was a special person and a friend for many of us and we dedicate this afternoon to his memory.