iten
Home » Evento (page 9)

Tag Archives: Evento scientifico

DAFNE-TF Workshop 2018

ICFA Mini-Workshop on   DAFNE as Open Accelerator Test Facility in year 2020 The workshop will take place on December 17th, 2018 at the Touschek Auditorium, Frascati Laboratory of INFN, Italy. The workshop is intended to discuss the interest from scientists to access the DAFNE e+ e- complex, which will conclude its physics program as collider in 2020. An infrastructure almost unique, that could open as Test Facility (DAFNE-TF) to the international community for studies of accelerator technologies and beam physics, for small experiments, and to be used as a test bed for enterprises active in the sector of components for accelerators.  Invitation Letter of Prof. Lenny Rivkin, Chair of the International Scientific Committee  INFN-18-10-LNF – “Proposal for a possible use of DAFNE as an open infrastructure (DAFNE-TF) for the study of physics and innovative technologies for accelerators” Scientific Committee L. Rivkin (EPFL and PSI, chair), C. Bloise (INFN-LNF), Y. Cai (SLAC), A. Ghigo (INFN-LNF), M. Giovannozzi (CERN), C. Milardi (INFN-LNF), N. Pastrone (INFN-Torino), A. Variola (INFN-LNF) Organizing Committee O. R. Blanco Garcia (INFN-LNF), S. Caschera (INFN-LNF), A. De Santis (INFN-LNF), A. Drago (INFN-LNF, chair) Secretariat D. Ferrucci (INFN-LNF), M. Luciani (INFN-LNF) dafne-tfw2018@lists.lnf.infn.it   Webmaster: S. Reda

Scopri di più »

Searching for the neutrinoless double beta decay with Gerda

Neutrinoless double beta decay is a lepton-number violating process which is predicted by many extensions of the Standard Model. It could be the key to understand the nature of the neutrino. If observed, it would prove its Majorana nature and the half-life of the decay would be a direct measure of the yet unknown absolute scale of the neutrino-mass, assuming the massive neutrino exchange as the dominant process. The GERmanium Detector Array (Gerda) experiment at the INFN, Gran Sasso Laboratory, Italy, is searching for the neutrinoless double beta decay of the isotope 76 Ge. High-purity germanium crystals enriched in 76 Ge are the source and the detector simultaneously. The key design feature of Gerda is that detectors are deployed directly into an ultrapure cryogenic liquid (liquid argon), acting both as cooling medium and radiation shield against the external radiation. After a major detector upgrade a second Phase (Phase II) of the experiment started in December 2015. Newly developed, custom-made BEGe-type germanium detectors made out of enriched material were deployed in the setup, allowing for a superior background rejection by pulse shape discrimination. The background suppression was further improved thanks to an active veto which detects the liquid argon scintillation light. This presentation will summarize the basic concept of the Gerda design, the recent physics results from Phase II, the status and future perspectives of the neutrinoless double beta decay search using 76 Ge.

Scopri di più »

THE CUORE EXPERIMENT AT LNGS

Neutrinoless double beta decay (NDBD) is a direct probe of new physics beyond the Standard Model. Its discovery would demonstrate that the lepton number is not a symmetry of nature and would provide unique information on the nature and mass of the neutrinos. Among the possible experimental techniques, thermal detectors fulfill the requirements for a sensitive search, showing an excellent energy resolution, an almost complete independence from the isotope choice and the possibility of scaling to very large masses. Characterized by an exceptionally high natural abundance in 130-Te and excellent mechanical and thermal properties, TeO2 has long been recognized as an ideal candidate, and a number of increasing mass bolometers have been developed along the past 30 years. The Cryogenic Underground Observatory for Rare Events (CUORE) is just the latest step of this development. With a mass of 741 kg, the detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The installation of the 19 towers in the CUORE cryostat was completed in August 2016, followed by the cooldown to base temperature in December 2016. This result marks a fundamental milestone in low temperature detectors techniques, opening the path for future ton-scale bolometric experiments searching for rare events. CUORE has been taking science data since Spring 2017, alternating engineering and physics runs. The performance of the detector and the initial results be presented.

Scopri di più »

A Hunt for Dark Matter: a Tale of Direction and Sensitivity

The WIMP direction at Earth undergoes a diurnal modulation that, if detected, would provide one of the most powerful and unambiguous signatures for the discovery of dark matter. Experimental efforts and ideas aimed at detecting this signature have greatly expanded in the last decade, which also saw significant technical progress overcoming a number of challenges. Despite this, the gap in limit-setting sensitivity between directional and non-directional searches has widened. Sensitivity to unexplored WIMP parameter space is, perhaps, the biggest challenge facing the directional community. In this regard, the recent prediction of an irreducible background from solar neutrinos has provided a needed impetus, leading to a resurgence in the field. Directional sensitivity provides the most robust path beyond this so called ‘neutrino-floor’. After briefly motivating the case for directionality I will focus on the experimental work in directionality by my group at UNM. Here I will begin with our work on the DRIFT experiment, which pioneered the use of negative-ion TPCs for directional DM searches. I will also describe R&D on improving directional and discrimination sensitivity with micro-patterned gas detectors. I will conclude with some new ideas that could lead to a simple, cheap and scalable path to the large volumes needed for future directional DM experiments.

Scopri di più »

Neutrino Lines from Dark Matter

While photon lines – or monochromatic photons-are known to arise in many dark matter models, neutrino lines are not so common. In this talk, I will discuss simple dark matter models, whose main indirect detection signature is the production of monochromatic neutrinos. Such features play an important role in indirect dark matter searches because they can be better discriminated against the astrophysical background. In the first part of my talk, I will discuss decaying dark matter. In particular, I will focus on singlet majorons, which naturally produce neutrino lines. Then, in the second part,I will briefly describe the properties that simple models must have in order to produce, in the near future,an observable flux of neutrino lines from dark matter annihilations. In both parts, I will discuss the implications for neutrino telescopes and the interplay with other indirect detection channels.

Scopri di più »

Fermilab: Muon g-2 and other news.

After 50 years of operation, Fermilab is still going strong. I will discuss the motivation, status, and prospects of the FNAL g-2 experiment. I’ll place it in historical context, especially regarding Fermilab’s future programs. I will end with a brief explanation of Fermilab’s “smallest” experiment, the Holometer, which measures effect of Planck-scale physics.

Scopri di più »

B-Physics Anomalies, Lepton Universality Violation and… Cosmology

A whole body of B-meson decays display persistent deviations with respect to the Standard-Model (SM) predictions. These deviations concern coherent sets of data, all of them with two leptons in the final state. Deviations are in the fact that decays to different leptons appear to depart or not from the SM predictions depending on the considered lepton. This can be explained by some new interaction that distinguishes between the lepton species, i.e. one that violates Lepton Universality (LU). After a review of the status and interpretation of data, we explore the question whether models for such beyond-SM effect may leave footprints in the cosmos, e.g. in observables related to Dark Matter or to neutrino fluxes.

Scopri di più »

The VHF-Gun Electron, an electron source optimized for high-brightness, high-duty-cycle applications.

In the last decade, the development/proposal of MHz-class repetition rate electron applications such as free electron lasers (FELs), inverse Compton scattering sources, and ultrafast electron diffraction and microscopy (UED/UEM), called for the development of new gun schemes capable of generating high brightness beams at such high rates. The VHF-Gun, a 186 MHz room-temperature continuous wave RF photo-gun developed at the Lawrence Berkeley Laboratory (LBNL) was one of the answers to that call. The VHF-Gun was constructed and tested in the APEX facility at LBNL successfully demonstrating all design parameters and the generation of electron beams with the required brightness. A close version of the APEX VHF-Gun was fabricated at LBNL and delivered to SLAC to operate as the electron source for the LCLS-II, the new X-ray FEL in construction at Stanford, and the original VHF-Gun is presently used for generating the beams for HiRES, the UED program at LBNL. But the game it is not over yet! For example, the recently approved upgrade of the LCLS-II towards higher energies (LCLS-II HE), and the always brightness-starving UED and UEM applications, would greatly benefit from a further increase of the electron beam brightness. In response to that, our group at LBNL started to study possible upgrades of the VHF-Gun scheme that would allow for the desired performance improvement. Several conceptual options were identified and last year, we received funds for developing such concepts up to a more mature level. After a description of the existing VHF-Gun and of its main experimental results, ...

Scopri di più »

γγ scattering and non-BFKL contribution to Pomeron

Abstract: Pomeron is a term introduced in the 1960’s in the frame- work of the phenomenological Regge theory. It describes the behavior of total cross-sections of any hadronic reaction at extremely large values of the invariant energy s. In the QCD context, the best-known contribution to the Pomeron comes from the BFKL equation This approach resums Leading Logarithmic (LL) contributions i.e. single-logarithmic (SL) contributions, ∼ (αs ln s)n, multiplied by the overall factor s. The high-energy asymptotics of this resummation is known as the BFKL Pomeron. It predicts the total cross-section of hadronic reactions (and the γγ-scattering in particular) to behave, asymptotically, as ∼ s∆, where the exponent ∆ is called the intercept of the BFKL Pomeron. In contrast, we calculate amplitude ADL of elastic γγ-scattering in the Double-Logarithmic approximation (DLA), accounting for contributions ∼ (αs ln2 s)n. They are not accompanied by the overall factor s, so asymptotics of ADL is ∼ s(∆DL−1) which looks negligibly small compared to the BFKL result. By this reason the DL contribution to Pomeron was offhandedly ignored by theoretical HEP society and full attention was focused on the BFKL Pomeron only. However, we demonstrate that the intercept ∆DL proves to be so large that its value compensates for the lack of the extra factor of s and makes the DL Pomeron of comparable importance to the BFKL Pomeron. It means that DL Pomeron should participate in theoretical analysis of all HEP results where the BFKL Pomeron has been involved.

Scopri di più »

Terahertz Driven Electron and X-ray Sources

Today, high brightness and highly relativistic electron beams are generated by circular or linear accelerators (LINAC) typically operating with 1-3 GHz accelerating frequencies and approaches towards X-band frequencies in the 10 GHz range are maturing. The achievable accelerating gradients are limited by field emission from cavity walls or pulsed heating to several tens of MV/m in the case of low frequencies and up to 100 MV/m in the case of X- band frequencies. Moving up in frequency to the THz range, here hundreds of GHz, experimentally confirmed scaling laws predict the realization of few-hundred MV/m to 1 GV/m accelerating fields in LINACs and guns, respectively. The high field strength and field gradients enable direct generation of single femtosecond electron bunches with substantial charge in the pC-range from very compact devices. We will discuss highly efficient laser based THz generation by optical rectification and first results towards THz based electron guns, LINACs and beam manipulations with the final goal to construct a hard-X-ray source producing attosecond pulses.

Scopri di più »