An innovative technique to access the nuclear matrix elements entering the expression of the life time of the double beta decay by relevant cross sections of double charge exchange reactions is ...proposed. The basic point is the coincidence of the initial and final state wave-functions in the two classes of processes and the similarity of the transition operators, which in both cases present a superposition of Fermi, Gamow-Teller and rank-two tensor components with a relevant implicit momentum transfer. First pioneering experimental results obtained at the INFN-LNS laboratory for the 40Ca(18O,18Ne)40Ar reaction at 270 MeV, give encouraging indication on the capability of the proposed technique to access relevant quantitative information. A key aspect of the project is the use of the K800 Superconducting Cyclotron (CS) for the acceleration of the required high resolution and low emittance heavy- ion beams and of the MAGNEX large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the high mass, angular and energy resolution required even at very low cross section. The LNS set-up is today an ideal one for this research even in a worldwide perspective. However a main limitation on the beam current delivered by the accelerator and the maximum rate accepted by the MAGNEX focal plane detector must be sensibly overcome in order to systematically provide accurate numbers to the neutrino physics community in all the studied cases. The upgrade of the LNS facilities in this view is part of this project.
Light dark matter searches with positrons Battaglieri, M.; Bianconi, A.; Bisio, P. ...
The European physical journal. A, Hadrons and nuclei,
08/2021, Volume:
57, Issue:
8
Journal Article
Peer reviewed
Open access
We discuss two complementary strategies to search for light dark matter (LDM) exploiting the positron beam possibly available in the future at Jefferson Laboratory. LDM is a new compelling hypothesis ...that identifies dark matter with new sub-GeV “hidden sector” states, neutral under standard model interactions and interacting with our world through a new force. Accelerator-based searches at the intensity frontier are uniquely suited to explore it. Thanks to the high intensity and the high energy of the Continuous Electron Beam Accelerator Facility (CEBAF) beam, and relying on a novel LDM production mechanism via positron annihilation on target atomic electrons, the proposed strategies will allow us to explore new regions in the LDM parameters space, thoroughly probing the LDM hypothesis as well as more general hidden sector scenarios.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The focal plane detector of the MAGNEX large acceptance magnetic spectrometer is presented. It is based on a large low-pressure gas-filled tracker followed by a wall of silicon detectors to stop the ...particles. It has been designed for the stringent requirements from the ion optics and the foreseen use with heavy ions. The performances of the device are demonstrated using 4MeV/
u
oxygen beams. The results of the tests are described and discussed in view of the application of the particle identification and trajectory reconstruction techniques to recover the kinematic properties of the reaction products. They demonstrate the suitability of such detector in a wide range of experiments where low-energy thresholds, large-accepted solid angle, precise momentum measurement and good particle identification are needed.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
6.
Pulse-shape discrimination in NE213 liquid scintillator detectors Cavallaro, M.; Tropea, S.; Agodi, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2013, Volume:
700
Journal Article
Peer reviewed
The 16-channel fast stretcher BaFPro module, originally developed for processing signals of Barium Fluoride scintillators, has been modified to make a high performing analog pulse-shape analysis of ...signals from the NE213 liquid scintillators of the EDEN neutron detector array. The module produces two Gaussian signals, whose amplitudes are proportional to the height of the fast component of the output light and to the total energy deposited into the scintillator, respectively. An in-beam test has been performed at INFN-LNS (Italy) demonstrating a low detection threshold, a good pulse-shape discrimination even at low energies and a wide dynamic range for the measurement of the neutrons energy.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We propose an experiment to search for a new gauge boson A' in e+e− annihilation by means of a positron beam incident on a gas hydrogen target internal to the bypass at the VEPP-3 storage ring. The ...search method is based on a missing mass spectrum in the reaction e+e−→γA'. It allows observation of the A' signal independently of its decay modes and life time. The projected result of this experiment corresponds to an upper limit on the square of the coupling constant ϵ2=3ċ10−8 with a signal-to-noise ratio of two to one at an A' mass of 5–20 MeV .
We report new results for the exclusive and quasi-free cross sections off neutrons bound in deuterium yvn(p) →p π-(p) are presented over a wide final state hadron angle range with a kinematic ...coverage of the invariant mass (W) up to 1.825 GeV and the virtual photon four-momentum transfer squared (Q2) from 0.4 to 1.0 GeV2. The exclusive structure functions have been extracted and their Legendre moments were obtained. Final-state-interaction contributions have been kinematically separated from the extracted quasi-free cross sections off bound neutrons solely based on the analysis of the experimental data. These new results will serve as long-awaited input for phenomenological analyses to extract the Q2 evolution of previously unavailable n → N* electroexcitation amplitudes and to improve state-of-the-art models of neutrino scattering off nuclei by augmenting the already available results from free protons.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
A novel mechanism to produce and detect light dark matter in experiments making use of GeV electrons (and positrons) impinging on a thick target (beam dump) is proposed. The positron-rich environment ...produced by the electromagnetic shower allows us to produce an A^{'} via nonresonant (e^{+}+e^{-}→γ+A^{'}) and resonant (e^{+}+e^{-}→A^{'}) annihilation on atomic electrons. The latter mechanism, for some selected kinematics, results in a larger sensitivity with respect to limits derived by the commonly used A^{'}-strahlung. This idea, applied to beam-dump experiments and active beam-dump experiments, pushes down the current limits by an order of magnitude.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
High-energy positron annihilation is a viable mechanism to produce dark photons (A′). This reaction plays a significant role in beam-dump experiments using multi-GeV electron beams on thick targets ...by enhancing the sensitivity to A′ production. The positrons produced by the electromagnetic shower can produce an A′ via nonresonant (e++e−→γ+A′) and resonant (e++e−→A′) annihilation on atomic electrons. For visible decays, the contribution of resonant annihilation results in a larger sensitivity with respect to limits derived by the commonly used A′-strahlung in certain kinematic regions. When included in the evaluation of the E137 beam-dump experiment reach, positron annihilation pushes the current limit on ϵ downwards by a factor of 2 in the range 33 MeV/c2<mA′<120 MeV/c2.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
PDF
