A large size, thin, high-quality polycrystalline diamond slab was used to build the full carbon active target of the PADME experiment. PADME is searching for a dark photon of mass up to 23.7 MeV, ...with a 550 MeV pulsed positron beam provided by the Beam Test Facility of the Laboratori Nazionali di Frascati. The target was built in the laboratories of INFN Lecce and University of Salento by realizing graphitic strips on both sides of a commercial CVD diamond sensor of 2×2cm2 cross section and 100 microns thickness, by means of a UV excimer laser. The strips, with 1mm pitch and oriented in orthogonal directions on the two surfaces, allow to reconstruct two views of the beam profile and to evaluate the particle multiplicity of each bunch. The detector was operated from September 2018 to end of February 2019. Here a review of the status, the operation experience, and the performance of the device in the PADME experiment is presented.
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
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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.
Abstract
The PADME experiment is designed to search for a
hypothetical dark photon
A
'
produced in positron-electron
annihilation using a bunched positron beam at the Beam Test Facility
of the INFN ...Laboratori Nazionali di Frascati. The expected
sensitivity to the
A
'
-photon mixing parameter
ϵ
is 10
-3
, for
A
'
mass ≤ 23.5 MeV/
c
2
after
collecting ∼ 10
13
positrons-on-target.
This paper presents the PADME detector status after commissioning in
July 2019. In addition, the software algorithms employed to
reconstruct physics objects, such as photons and charged particles,
and the calibration procedures adopted are illustrated in detail.
The results show that the experimental apparatus reaches the design
performance, and is able to identify and measure standard
electromagnetic processes, such as positron bremsstrahlung and
electron-positron annihilation into two photons.
The PADME experiment at the LNF Beam Test Facility searches for dark photons produced in the annihilation of positrons with the electrons of a fixed target. The strategy is to look for the reaction ...e++e−→γ+A′, where A′ is the dark photon, which cannot be observed directly or via its decay products. The electromagnetic calorimeter plays a key role in the experiment by measuring the energy and position of the final-state γ. The missing four-momentum carried away by the A′ can be evaluated from this information and the particle mass inferred. This paper presents the design, construction, and calibration of the PADME's electromagnetic calorimeter. The results achieved in terms of equalisation, detection efficiency and energy resolution during the first phase of the experiment demonstrate the effectiveness of the various tools used to improve the calorimeter performance with respect to earlier prototypes.
Abstract
During 2022 data taking (Run III) PADME searched for a resonant production and a visible decay of the X17 particle into e
+
e
-
. A precise knowledge within 1% uncertainty of the number of ...positrons was required for the observation. To that purpose, an array of 2 × 6 Timepix3 (total of 512 × 1536 pixels) hybrid pixel detectors operated in data-streaming mode with ToA resolution of 1.56 ns for every pixel was employed. Two methods for data acquisition were developed. A frame-based method, integrating the number of hits for each individual pixel for a predefined period of time served for monitoring the beam conditions and to provide a rough estimation of the beam distribution and number of positrons. A data streaming mode exploiting the nanosecond time resolution of Timepix3 detector was used for precise characterization of the transverse beam profile and the distribution of the incident positrons within each bunch of ∼ 200 ns duration.
Abstract
The PADME experiment at LNF-INFN employs positron-on-target-annihilation
to search for new light particles. Crucial parts of the experiment are the charged
particle detectors, composed of ...plastic scintillator bars with light transmitted
by wavelength shifting fibers to silicon photomultipliers (SiPMs). The location of
the detector — close to a turbomolecular pump, inside a vacuum tank, and exposed
to 0.5 T magnetic field — has driven the design of custom modular SiPM front-end
and power supply electronics. The design of the system and its performance, confirming
the desired sub-ns resolution on the reconstructed particle flying times, is shown
and discussed.
Abstract
PADME (Positron Annihilation into Dark Matter Experiment) is a fixed target experiment located at the Beam Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) designed to ...search for a massive dark photon
A
′
in the process
e
+
e
−
→
γ
A
′
, using a positron beam of energy up to 550 MeV. The experiment exploits the missing mass technique which allows for a search of
A
′
in a model independent way. A sensitivity on the mixing constant
ϵ
> 10
−3
for a dark photon mass in the range
1
≤
m
A
′
≤
23.7
MeV
/c
2
can be achieved by collecting 4 × 10
13
positrons on target. Run 2 data taking finished in December 2020 and allowed to reach an integrated luminosity of 5 × 10
12
positrons on target.
Particle physics today faces the challenge of explaining the mystery of dark matter, the origin of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent fine-tuning ...of the electro-weak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to familiar matter, below the GeV-scale, or even radically below, down to sub-eV scales, and with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and indeed, existing data provide numerous hints for such possibility. A vibrant experimental program to discover such physics is under way, guided by a systematic theoretical approach firmly grounded on the underlying principles of the Standard Model. This document represents the report of the FIPs 2022 workshop, held at CERN between the 17 and 21 October 2022 and aims to give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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