Commissioning of the PADME experiment with a positron beam
P. Albicocco, R. Assiro, F. Bossi, P. Branchini, B. Buonomo, V. Capirossi, E. Capitolo, C. Capoccia, A. P. Caricato, S. Ceravolo, G. Chiodini, G. Corradi, R. De… 展开作者
P. Albicocco, R. Assiro, F. Bossi, P. Branchini, B. Buonomo, V. Capirossi, E. Capitolo, C. Capoccia, A. P. Caricato, S. Ceravolo, G. Chiodini, G. Corradi, R. De Sangro, C. Di Giulio, D. Domenici, F. Ferrarotto, S. Fiore, G. Finocchiaro, L. G Foggetta, A. Frankenthal, M. Garattini, G. Georgiev, F. Giacchino, A. Ghigo, P. Gianotti, F. Gontad, F. Iazzi, S. Ivanov, Sv. Ivanov, V. Kozhuharov, E. Leonardi, E. Long, M. Martini, M. Martino, A. Miccoli, I. Oceano, F. Oliva, G. C. Organtini, F. Pinna, G. Piperno, C. Pinto, M. Raggi, F. Safai Tehrani, A. Saputi, I. Sarra, B. Sciascia, R. Simeonov, T. Spadaro, S. Spagnolo, E. Spiriti, D. Tagnani, l. Tsankov, C. Taruggi, P. Valente, A. Variola, E. Vilucchi
The PADME experiment is designed to search for a hypothetical dark photon $A^{\prime}$ 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 $A^{\prime}$-photon mixing parameter $ε$ is 10$^{-3}$, for $A^{\prime}$ mass $\le$ 23.5 MeV/$c^{2}$ after collecting $\sim 10^{13}$ 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, electron-positron annihilation into two photons.
PADME is a fixed-target, missing-mass experiment at the Laboratori Nazionali di Frascati (LNF) to search for evidence of dark photons. It has collected a first set of commissioning data in 2018/2019 which will also be used for preliminary data analysis. PADME is expected to reach a sensitivity of up to $10^{-8}$ in $ε^2$ (kinetic mixing coefficient) for low-mass dark photons ($\sim$ few MeV). Here we describe PADME's design, status of the experiment, and future plans.
The PADME experiment will search for the invisible decay of Dark Photons produced in interactions of positron from the DA$Φ$NE Linac on a target. The collaboration aims at reaching a sensitivity of $\sim10^{-3}$ on the coupling constant for values of Dark Photon masses up to $23.7\,\mbox{MeV}$.
The Positron Annihilation into Dark Matter Experiment (PADME) at LNF-INFN Linac aims to perform a search for dark photons in positron-on-target annihilation process. A key component of the setup is the tracking system which allows vetoing the bremsstrahlung-induced background. Different solutions for the detector will be shown and will be discussed. Attention will be paid to the possibility to construct a hybrid tracker based on plastic scintillator fibers read out by CCD matrices.
The PADME experiment at the DA$Φ$NE Beam-Test Facility (BTF) is designed to search for the gauge boson of a new $\rm U(1)$ interaction in the process e$^+$e$^-\rightarrowγ$+$\rm A'$, using the intense positron beam hitting a light target. The $\rm A'$, usually referred as dark photon, is assumed to decay into invisible particles of a secluded sector and it can be observed by searching for an anomalous peak in the spectrum of the missing mass measured in events with a single photon in the final state. The measurement requires the determination of the 4-momentum of the recoil photon, performed b…
Massive photon-like particles are predicted in many extensions of the Standard Model with a hidden sector where dark matter is secluded. They are vector bosons mediating the interaction between dark matter particles and can be produced in scattering of ordinary particles through a faint mixing to the photon. Most of the present experimental constraints on this "dark photon" (A') rely on the hypothesis of dominant decays to lepton pairs. The PADME experiment will search for the e$^+$e$^- \rightarrow γ$A' process in a positron-on-target experiment, assuming a decay of the A' into invisible parti…
The PADME experiment, hosted at the Laboratori Nazionali di Frascati in Italy, is dedicated to the dark photon search. It looks for the reaction $e^{+}\,e^{-}\rightarrow A'\,γ$, where $A'$ indicates the dark photon. The $550\,\text{MeV}$ positrons beam that impinges on electrons, coming from an active diamond target, allows to scan $A'$ masses up to $23.7\,\text{MeV}$. In this context, the segmented electromagnetic calorimeter plays a fundamental role, since it measures the final photon four-momentum. It consists of $616$ BGO crystals displaced in a cylindrical shape of $\approx29\,\text{cm}$ …
The PADME experiment at the LNF Beam Test Facility searches for dark photons produced in the annihilation of positrons with the electrons of a fix target. The strategy is to look for the reaction $e^{+}+e^{-}\rightarrow γ+A'$, 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,…
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging of the whole human body as well as for physics studies involving detection of electron-positron annihilation into photons. J-PET has high angular and time resolution and allows for measurement of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for background rejection in the decays of positronium atoms.
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET device built from plastic scintillators. It is a multi-purpose detector designed for medical imaging and for studies of properties of positronium atoms in porous matter and in living organisms. In this article we report on the commissioning of the J-PET detector in view of studies of positronium decays. We present results of analysis of the positron lifetime measured in the porous polymer. The obtained results prove that J-PET is capable of performing simultaneous imaging of the density distribution of annihilation points as…
The Muon g-2 Experiment (E989) at Fermilab is seeking to measure the anomalous magnetic moment of muon ($a_μ$) with a precision of 140 parts-per-billion (ppb) and aiming to resolve the discrepancy between the E821 measurement and the Standard Model calculation of $a_μ$. In E989, the muon beam is stored in a ring magnet. The anomalous spin precession frequency $ω_{a}$ is measured by counting decay positrons in 24 calorimeters, and the magnetic field is measured by nuclear magnetic resonance (NMR) probes. Improvements in this experiment with respect to its predecessor and the progress achieved i…
The SoLid experiment aims to measure neutrino oscillation at a baseline of 6.4 m from the BR2 nuclear reactor in Belgium. Anti-neutrinos interact via inverse beta decay (IBD), resulting in a positron and neutron signal that are correlated in time and space. The detector operates in a surface building, with modest shielding, and relies on extremely efficient online rejection of backgrounds in order to identify these interactions. A novel detector design has been developed using 12800 5 cm cubes for high segmentation. Each cube is formed of a sandwich of two scintillators, PVT and 6LiF:ZnS(Ag), …
We describe the design, construction and performance of the PIBETA detector built for the precise measurement of the branching ratio of pion beta decay, pi+ -> pi0 e+ nu, at the Paul Scherrer Institute. The central part of the detector is a 240-module spherical pure CsI calorimeter covering 3*pi sr solid angle. The calorimeter is supplemented with an active collimator/beam degrader system, an active segmented plastic target, a pair of low-mass cylindrical wire chambers and a 20-element cylindrical plastic scintillator hodoscope. The whole detector system is housed inside a temperature-controll…
The reconstruction of the positron trajectory in the MEG-II experiment searching for the $μ^+ \to e^+ γ$ decay uses a cylindrical drift chamber operated with a helium-isobutane gas mixture. A stable performance of the detector in terms of its electron drift properties, avalanche multiplication, and with a gas mixture of controlled composition and purity has to be provided and continuously monitored. In this paper we describe the strategies adopted to meet the requirements imposed by the target sensitivity of MEG-II, including the construction and commissioning of a small chamber for an online …
The upcoming Mu3e experiment searches for the lepton flavour violating decay $μ^+\,\rightarrow\,e^+ e^- e^+$ with the aim of a final sensitivity of one signal decay in $10^{16}$ observed muon decays, an improvement over the preceding SINDRUM experiment by four orders of magnitude. In the first phase, the experiment will be operated at an existing intense muon beam line at the Paul Scherrer Institute. With muon stopping rates of about $10^{8}\text{s}^{-1}$, a single-event sensitivity of $2\cdot 10^{-15}$ can be achieved. For the ultimate sensitivity, a new high intensity muon beam line is requi…
We report on the design, construction, commissioning, and performance of a threshold gas Čerenkov counter in an open configuration, which operates in a high luminosity environment and produces a high photo-electron yield. Part of a unique open geometry detector package known as the Big Electron Telescope Array, this Čerenkov counter served to identify scattered electrons and reject produced pions in an inclusive scattering experiment known as the Spin Asymmetries of the Nucleon Experiment E07-003 at the Thomas Jefferson National Accelerator Facility (TJNAF) also known as Jefferson Lab. The exp…
We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1 T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4 K and are read out by silicon photomultipliers (MPPCs) at near room temperature. FACT provides the antiproton/antihydrogen annihilation position information with a few ns timing resolution. We present the hardware and software developments which led to the successful opera…
We propose a new measurement of the ratio of positron-proton to electron-proton, elastic scattering at DESY to determine the contributions beyond single-photon exchange, which are essential to the QED description of the most fundamental process in hadronic physics. A 20~cm long liquid hydrogen target together with the extracted beam from the DESY synchrotron would yield an average luminosity of $2.12\times10^{35}$~cm$^{-2}\cdot$s$^{-1}\cdot$sr$^{-1}$ ($\sim200$ times the luminosity achieved by OLYMPUS). A commissioning run at 2 GeV followed by measurements at 3 GeV would provide new data up to…
