In this work we consider a model including dark sector bosons interacting through tensor currents with Standard Model leptons. We show that for certain values of the interaction constant this model ...has the potential of providing an explanation for the discrepancy between theory and experiment, regarding the anomalous magnetic moment of the muon. The effect on the already established measurements for the electron are small and the lepton universality violation is naturally incorporated. Possible experimental searches together with systematic approach to characteristic properties of the final states are discussed.
The phenomenological implications to the decay of the neutral pion from the introduction of new dark particles are discussed. We calculate the contribution to the π0 decay width and then we extend ...the theory by adding dark sector vector particles which interact through γμ, σμν and σμνγ5. We calculate the total decay width of π0→γe+e− where the electron-positron pair is produced through a decay of a dark meson. The implication of the presented model on the present and future searches for new dark particles is also discussed.
We propose the first
Se
arch for
D
ark
S
ector at the Brazilian Synchrotron Light Laboratory, site of Sirius, a fourth-generation storage ring. We show that UVX, Sirius predecessor, can be a ...promising dark sector detector,
SeDS
, with unprecedented sensitivity. The search is based on a
1
-
3
GeV positron beam impinging on a thick target leading the
e
+
e
-
→
γ
A
′
reaction, followed by a missing mass spectrum event reconstruction. We show that
SeDS
has the potential to probe dark photons with masses up to 55 MeV and kinetic coupling down to
ϵ
2
∼
10
-
12
. Therefore, such experiment would constitute the best dark photon probe worldwide in the
10
-
55
MeV mass range, being able to probe an unexplored region of parameter space.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
4.
The PADME experiment at LNF Raggi, M; Kozhuharov, V; Valente, P
EPJ Web of Conferences,
2015, Letnik:
96
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Massive photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The ...PADME experiment proposes a search for the dark photon (A′) in the e+ e− → γA′ process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to 10−6 is achievable, in the mass region from 2.5 MeV < MA′ < 22.5 MeV. The proposed experimental setup and the analysis technique is discussed.
Light dark matter searches with positrons Battaglieri, M.; Bianconi, A.; Bisio, P. ...
The European physical journal. A, Hadrons and nuclei,
08/2021, Letnik:
57, Številka:
8
Journal Article
Recenzirano
Odprti dostop
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.
The PADME beam line Monte Carlo simulation Bossi, F.; Branchini, P.; Buonomo, B. ...
The journal of high energy physics,
09/2022, Letnik:
2022, Številka:
9
Journal Article
Recenzirano
Odprti dostop
A
bstract
The PADME experiment at the DAΦNE Beam-Test Facility (BTF) of the INFN Laboratory of Frascati is designed to search for invisible decays of dark sector particles produced in ...electron-positron annihilation events with a positron beam and a thin fixed target, by measuring the missing mass of single-photon final states. The presence of backgrounds originating from beam halo particles can significantly reduce the sensitivity of the experiment. To thoroughly understand the origin of the beam background contribution, a detailed G
eant
4-based Monte Carlo simulation has been developed, containing a full description of the detector together with the beam line and its optical elements. This simulation allows the full interactions of each particle to be described, both during beam line transport and during detection, a possibility which represents an innovative way to obtain reliable background predictions.
Time over threshold in the presence of noise Gonnella, F.; Kozhuharov, V.; Raggi, M.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2015, Letnik:
791
Journal Article
Recenzirano
Odprti dostop
The Time-over-Threshold (ToT) technique is a widely used quantity to measure the energy deposited in various detectors in particle physics. In this paper we present the studies of its behavior in the ...presence of noise. The ToT distributions from cosmic-ray data showed several equally spaced peaks that were successfully modeled due to a sinusoidal noise pick-up. The effects of that noise on the detection efficiency and energy resolution are also discussed.
A possible solution to the dark matter problem postulates that dark particles can interact with Standard Model particles only through a new force mediated by a "portal". If the new force has a U(1) ...gauge structure, the "portal" is a massive photon-like vector particle, called dark photon or A′. The PADME experiment at the DAΦNE Beam-Test Facility (BTF) in Frascati is designed to detect dark photons produced in positron on fixed target annihilations decaying to dark matter (e+e-→γA′) by measuring the final state missing mass. The experiment will be composed of a thin active diamond target where a 550 MeV positron beam will impinge to produce e+e- annihilation events. The surviving beam will be deflected with a magnet while the photons produced in the annihilation will be measured by a calorimeter composed of BGO crystals. To reject the background from Bremsstrahlung gamma production, a set of segmented plastic scintillator vetoes will be used to detect positrons exiting the target with an energy lower than that of the beam, while a fast small angle calorimeter will be used to reject the e+e-→γγ(γ) background. To optimize the experimental layout in terms of signal acceptance and background rejection, the full layout of the experiment was modelled with the GEANT4 simulation package. In this paper we will describe the details of the simulation and report on the results obtained with the software.
Precision measurement of the energy and direction of gamma-rays plays a key role in many fields such as medical imaging, nuclear spectroscopy, and astrophysics. In astrophysics position sensitive ...gamma-ray detectors are used to study diffuse and point-like sources. These space-born gamma-ray telescopes, however, are mainly based on large arrays of detectors which are expensive, complex, and take long time to build. A different approach is the use of detector with similar energy and angular resolution, but small enough to be deployed on nanosatellites. We research a design based on monolithic scintillator and multi-pixel photo-sensor. At first we are focused on characterization of CeBr3 scintillator detectors. Bench test experiments were performed with CeBr3 crystal with square surfaces and thicknesses of 10 mm and 25 mm. The crystals were coupled to a single-anode PMT and the outcome compared to Geant4 simulation.
The measurement of BR(K+→π+νν̄) with 10% precision by the NA62 experiment requires extreme background suppression. The Small Angle Calorimeter aims to provide an efficient veto for photons flying at ...angles down to zero with respect to the kaon flight direction. The initial prototype was upgraded and tested at the Beam Test Facility of the DAΦNE Linac at Frascati. The energy resolution and the efficiency were measured and are presented.
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