We have measured the cross section σ(e+e−→π+π−γ(γ)) at DAΦNE, the Frascati ϕ-factory, using events with initial state radiation photons emitted at small angle and inclusive of final state radiation. ...We present the analysis of a new data set corresponding to an integrated luminosity of 240 pb−1. We have achieved a reduced systematic uncertainty with respect to previously published KLOE results. From the cross section we obtain the pion form factor and the contribution to the muon magnetic anomaly from two-pion states in the mass range 0.592<Mππ<0.975 GeV. For the latter we find Δππaμ=(387.2±0.5stat±2.4exp±2.3th)×10−10.
Abstract
In dark matter studies, the absence of experimental evidences other than the astrophysical observations, has triggered new approaches. Nowadays, many particle physics experiments at ...accelerators are trying to contribute by looking for signals of hidden particles postulated by different theoretical extensions of the Standard Model. This results in a vaste hunting for new particles with a wide range of properties with the intention to also give reason to other unexplained particle physics phenomena. Within this scenario is inserted the Positron Annihilation into Dark Matter Experiment (PADME) ongoing at the Laboratori Nazionali di Frascati of INFN that is looking for signals of hidden particles by studying the annihilations of a positron beam with the electrons of a fixed target. PADME had, up to now, two data taking periods devoted to the search of a dark photon signal, but its setup turned out to be also suited to explore the existence of a protophobic new boson of mass 17 MeV/
c
2
postulated to explain an anomalous effect observed by a Hungarian group while studying nuclear excited states. In this paper it is reported an overview of the PADME experiment and of the modifications implemented to allow a dedicated data taking at 282 MeV beam energy, meant to produce the new particle at resonance.
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.
The NA62 experiment at CERN SPS aims at measuring-100 events of the very rare decay K+ →π +ννˉ (BR∼8.5xlO∼10). It poses stringent requirements on PID capabilities to reject the overwhelming π+π0 ...(63%) and Kμ2(21%) backgrounds. The photon veto system must provide a rejection factor of 10∼8 on π0 decays. As a main γ veto detector, the NA48 liquid Kripton calorimeter will be used. To have full geometrical acceptance up to 50 mr, a set of 12 veto stations should be placed along the vacuum decay tank, with an inefficiency <10∼4 in a wide energy range (200 MeV-35 GeV). Good energy resolution (∼10% at 1 GeV) for threshold definition, good time resolution (∼1 ns) to be used at the trigger level, sensitivity to MIP for calibration with muons of the beam halo are needed. A moderate segmentation in the azimuthal angle is desirable, for reducing the counting rate and providing information on the γ direction. We performed an intense R&D program on three solutions: “spaghetti” calorimeter, lead/scintillator sandwich calorimeter, and original re-use of the existing barrel of the OPAL lead-glass e.m. calorimeter. Studies have been performed at the Frascati BTF beam and all three meet the efficiency requirements. The final choice uses a peculiar radial arrangement of lead-glasses in rings. Front-end electronics has been designed to cover the tree orders of magnitude of the signal, contributing to the trigger, and integrated in the general TDAQ, while keeping low cost and simplicity. The first five full veto stations have been constructed. Two tests have been done and problems found fixed. We will discuss about R&D for the technology choice, LAV construction, test beams results and simulation performance.
The charged particle veto system of the PADME experiment Oliva, F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
The PADME (Positron Annihilation into Dark Matter Experiment) will search for the production of a dark photon from positron–electron annihilation e+e−→γA′ using the positron beam of the Beam Test ...Facility (BTF) of the DAΦNE Linac at Laboratori Nazionali di Frascati (LNF). This paper presents the status of the charged particle veto system which is necessary to tag bremsstrahlung processes which are the main source of background events.
The PADME experiment, at the Laboratori Nazionali di Frascati (LNF) of INFN, is designed to be sensitive to the production of a low mass gauge boson A′ of a new U(1) symmetry holding for dark ...particles. The DAΦNE Beam-Test Facility of LNF is providing a high intensity, mono-energetic positron beam impacting on a low Z target to provide e+e− annihilations, where the dark photon can be produced along with an ordinary photon. Simulation studies predict a sensitivity on the interaction strength (ε2 parameter) down to 10−6, in the mass region 1 MeV/c2<MA′<23.7 MeV/c2, for one year of data taking with a 550 MeV beam. In 2018 the first run will take place, and early data will give the opportunity to compare the detector performance with the design parameters. Right now, an intense activity is taking place to install and commission the PADME experimental apparatus on site.
The calorimeters of the PADME experiment Gianotti, P.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
The PADME experiment is under construction at the Frascati National Laboratories of INFN to explore the coupling between ordinary and dark matter. This will be done through the detection of Standard ...Model photons produced in the reaction e+e−→γA′. The measurement of the photons 4-momentum allows to reconstruct the missing mass spectrum of this process, where the A′ could appear as a peak. To this purpose, two independent electromagnetic calorimeters are used. The layout of the two detectors, and their expected performance measured during prototypes tests, are here presented.
PADME (Positron Annihilation into Dark Matter Experiment) is an experiment that will search for the production of a dark photon A′ from the annihilation of a positron beam on a thin diamond target. ...It will use the 550 MeV positron beam of the Beam Test Facility (BTF) of the Laboratori Nazionali di Frascati (LNF) of INFN. According to the PADME design, the region of sensitivity is MA′≤23.7 MeV/c2 and ϵ2>10−6, where MA′ and ϵ are the dark photon mass and the A′γ mixing parameter.
This paper presents the status of the active diamond target, in particular the assembly of two 32 channel targets of polycrystalline Chemical Vapor Deposition (CVD) diamond, one with graphitic strips and another with traditional CrAu strips.
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