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M. Tenti

Publications and source records attributed to M. Tenti.

At least 37 records · Page 2Linked to original sources
arXiv2020

Decay tunnel instrumentation for the ENUBET neutrino beam

The uncertainty in the initial neutrino flux is the main limitation for a precise determination of the absolute neutrino cross section. The ERC funded ENUBET project (2016-2021) is studying a facility based on a narrow band beam to produce an intense source of electron neutrinos with a ten-fold improvement in accuracy. Since March 2019 ENUBET is also a Neutrino Platform experiment at CERN: NP06/ENUBET. A key element of the project is the instrumentation of the decay tunnel to monitor large angle positrons produced together with $ν_e$ in the three body decays of kaons ($K_{e3}$) and to discriminate them from neutral and charged pions. The need for an efficient and high purity e/$π$ separation over a length of several meters, and the requirements for fast response and radiation hardness imposed by the harsh beam environment, suggested the implementation of a longitudinally segmented Fe/scintillator calorimeter with a readout based on WLS fibers and SiPM detectors. An extensive experimental program through several test beam campaigns at the CERN-PS T9 beam line has been pursued on calorimeter prototypes, both with a shashlik and a lateral readout configuration. The latter, in which fibers collect the light from the side of the scintillator tiles, allows to place the light sensors away from the core of the calorimeter, thus reducing possible irradiation damages with respect to the shashlik design. This contribution will present the achievements of the prototyping activities carried out, together with irradiation tests made on the Silicon Photo-Multipliers. The results achieved so far pin down the technology of choice for the construction of the 3 m long demonstrator that will take data in 2021.

physics.ins-det↗
arXiv2020

Cryogenic SiPM arrays for the DUNE photon detection system

In this paper we report on the characterization of SiPM tiles developed for the R & D on the DUNE Photon Detection System. The tiles were produced by Fondazione Bruno Kessler (FBK) employing NUV-HD-SF SiPMs. Special emphasis is given on cryo-reliability of the sensors, i.e. the stability of electric and mechanical properties after thermal cycles at room and 77K temperature. The characterization includes the determination of the I-V curve, a high sensitivity measurement of Dark Count Rate at different overvoltages, and correlated noise. The single p.e. sensitivity is measured as a function of the number of sensors connected to a single electronic channel, after amplification at 77K using a dedicated cold amplifier.

physics.ins-det↗
arXiv2020

Polysiloxane-based scintillators for shashlik calorimeters

We present the first application of polysiloxane-based scintillators as active medium in a shashlik sampling calorimeter. These results were obtained from a testbeam campaign of a $\sim$6$\times$6$\times$45 cm$^3$ (13 $X_0$ depth) prototype. A Wavelength Shifting fiber array of 36 elements runs perpendicularly to the stack of iron (15 mm) and polysiloxane scintillator (15 mm) tiles with a density of about one over cm$^2$. Unlike shashlik calorimeters based on plastic organic scintillators, here fibers are optically matched with the scintillator without any intermediate air gap. The prototype features a compact light readout based on Silicon Photo-Multipliers embedded in the bulk of the detector. The detector was tested with electrons, pions and muons with energies ranging from 1 to 7 GeV at the CERN-PS. This solution offers a highly radiation hard detector to instrument the decay region of a neutrino beam, providing an event-by-event measurement of high-angle decay products associated with neutrino production (ENUBET, Enhanced NeUtrino BEams from kaon Tagging, ERC project). The results in terms of light yield, uniformity and energy resolution, are compared to a similar calorimeter built with ordinary plastic scintillators.

physics.ins-det↗
arXiv2019

Magnetic monopole search with the full MoEDAL trapping detector in 13 TeV $pp$ collisions interpreted in photon-fusion and Drell-Yan production

MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb$^{-1}$ of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, 1/2 and 1 are considered and both velocity-independent and -dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

hep-ex↗
arXiv2019

The ENUBET narrow band neutrino beam

The narrow band beam of ENUBET is the first implementation of the "monitored neutrino beam" technique proposed in 2015. ENUBET has been designed to monitor lepton production in the decay tunnel of neutrino beams and to provide a 1% measurement of the neutrino flux at source. In particular, the three body semi-leptonic decay of kaons monitored by large angle positron production offers a fully controlled $ν_{e}$ source at the GeV scale for a new generation of short baseline experiments. In this contribution the performances of the positron tagger prototypes tested at CERN beamlines in 2016-2018 are presented.

physics.ins-det↗
arXiv2019

Irradiation and performance of RGB-HD Silicon Photomultipliers for calorimetric applications

Silicon Photomultipliers with cell-pitch ranging from 12 $μ$m to 20 $μ$m were tested against neutron irradiation at moderate fluences to study their performance for calorimetric applications. The photosensors were developed by FBK employing the RGB-HD technology. We performed irradiation tests up to $2 \times 10^{11}$ n/cm$^2$ (1 MeV eq.) at the INFN-LNL Irradiation Test facility. The SiPMs were characterized on-site (dark current and photoelectron response) during and after irradiations at different fluences. The irradiated SiPMs were installed in the ENUBET compact calorimetric modules and characterized with muons and electrons at the CERN East Area facility. The tests demonstrate that both the electromagnetic response and the sensitivity to minimum ionizing particles are retained after irradiation. Gain compensation can be achieved increasing the bias voltage well within the operation range of the SiPMs. The sensitivity to single photoelectrons is lost at $\sim 10^{10}$ n/cm$^2$ due to the increase of the dark current.

physics.ins-det↗
arXiv2019

A high precision neutrino beam for a new generation of short baseline experiments

The current generation of short baseline neutrino experiments is approaching intrinsic source limitations in the knowledge of flux, initial neutrino energy and flavor. A dedicated facility based on conventional accelerator techniques and existing infrastructures designed to overcome these impediments would have a remarkable impact on the entire field of neutrino oscillation physics. It would improve by about one order of magnitude the precision on $ν_μ$ and $ν_e$ cross sections, enable the study of electroweak nuclear physics at the GeV scale with unprecedented resolution and advance searches for physics beyond the three-neutrino paradigm. In turn, these results would enhance the physics reach of the next generation long baseline experiments (DUNE and Hyper-Kamiokande) on CP violation and their sensitivity to new physics. In this document, we present the physics case and technology challenge of high precision neutrino beams based on the results achieved by the ENUBET Collaboration in 2016-2018. We also set the R&D milestones to enable the construction and running of this new generation of experiments well before the start of the DUNE and Hyper-Kamiokande data taking. We discuss the implementation of this new facility at three different level of complexity: $ν_μ$ narrow band beams, $ν_e$ monitored beams and tagged neutrino beams. We also consider a site specific implementation based on the CERN-SPS proton driver providing a fully controlled neutrino source to the ProtoDUNE detectors at CERN.

physics.ins-det↗
arXiv2018

Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb$^{-1}$ of 13 TeV proton-proton collisions at the LHC

We update our previous search for trapped magnetic monopoles in LHC Run 2 using nearly six times more integrated luminosity and including additional models for the interpretation of the data. The MoEDAL forward trapping detector, comprising 222~kg of aluminium samples, was exposed to 2.11~fb$^{-1}$ of 13 TeV proton-proton collisions near the LHCb interaction point and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to the Dirac charge or above are excluded in all samples. The results are interpreted in Drell-Yan production models for monopoles with spins 0, 1/2 and 1: in addition to standard point-like couplings, we also consider couplings with momentum-dependent form factors. The search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

hep-ex↗
arXiv2018

A narrow band neutrino beam with high precision flux measurements

The ENUBET facility is a proposed narrow band neutrino beam where lepton production is monitored at single particle level in the instrumented decay tunnel. This facility addresses simultaneously the two most important challenges for the next generation of cross section experiments: a superior control of the flux and flavor composition at source and a high level of tunability and precision in the selection of the energy of the outcoming neutrinos. We report here the latest results in the development and test of the instrumentation for the decay tunnel. Special emphasis is given to irradiation tests of the photo-sensors performed at INFN-LNL and CERN in 2017 and to the first application of polysiloxane-based scintillators in high energy physics.

physics.ins-det↗
arXiv2018

Testbeam performance of a shashlik calorimeter with fine-grained longitudinal segmentation

An iron- plastic-scintillator shashlik calorimeter with a 4.3 $X_0$ longitudinal segmentation was tested in November 2016 at the CERN East Area facility with charged particles up to 5 GeV. The performance of this detector in terms of electron energy resolution, linearity, response to muons and hadron showers are presented in this paper and compared with simulation. Such a fine-grained longitudinal segmentation is achieved using a very compact light readout system developed by the SCENTT and ENUBET Collaborations, which is based on fiber-SiPM coupling boards embedded in the bulk of the detector. We demonstrate that this system fulfills the requirements for neutrino physics applications and discuss performance and additional improvements.

physics.ins-det↗
arXiv2017

Determination of the neutrino mass hierarchy with a new statistical method

Nowadays neutrino physics is undergoing a change of perspective: the discovery period is almost over and the phase of precise measurements is starting. Despite the limited statistics collected for some variables, the three--flavour oscillation neutrino framework is strengthening well. In this framework a new method has been developed to determine the neutrino mass ordering, one of the still unknown and most relevant parameters. The method is applied to the 2015 results of the NOvA experiment for $ν_μ\rightarrow ν_e$ appearance, including its systematic errors. A substantial gain in significance is obtained compared to the traditional $Δχ^2$ approach. Perspectives are provided for future results obtainable by NOvA with larger exposures. Assuming the number of the 2015 $ν_e$ observed events scales with the exposure, an increase in only a factor three would exclude the inverted hierarchy at more than 95\% C.L. over the full range of the CP violating phase. The preliminary 2016 NOvA measurement on \numunue appearance has also been analyzed.

hep-ph↗
arXiv2017

Search for Sterile Neutrinos in the Muon Neutrino Disappearance Mode at FNAL

The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the {\em muon--neutrino disappearance} measurements at short baselines in order to put severe constraints to models with more than the three--standard neutrinos. To this aim the current FNAL--Booster neutrino beam for a Short--Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA--like spectrometers. The study was constrained by the availability of existing hardware and a time--schedule compatible with the undergoing project of multi--site Liquid--Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the $ν_μ$ disappearance and the $ν_e$ appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of $ν_μ$ disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far.

hep-ph↗
arXiv2017

Search for magnetic monopoles with the MoEDAL forward trapping detector in 13 TeV proton-proton collisions at the LHC

MoEDAL is designed to identify new physics in the form of long-lived highly-ionising particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC run-1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV $pp$ collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

hep-ex↗
arXiv2016

Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area $\sim$18 m$^2$, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb$^{-1}$. No magnetic charge exceeding $0.5g_{\rm D}$ (where $g_{\rm D}$ is the Dirac magnetic charge) is measured in any of the exposed samples, allowing limits to be placed on monopole production in the mass range 100 GeV$\leq m \leq$ 3500 GeV. Model-independent cross-section limits are presented in fiducial regions of monopole energy and direction for $1g_{\rm D}\leq|g|\leq 6g_{\rm D}$, and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for $1g_{\rm D}\leq|g|\leq 4g_{\rm D}$. Under the assumption of Drell-Yan cross sections, mass limits are derived for $|g|=2g_{\rm D}$ and $|g|=3g_{\rm D}$ for the first time at the LHC, surpassing the results from previous collider experiments.

hep-ex↗
arXiv2016

Test of scintillating bars coupled to Silicon Photomultipliers for a charged particle tracking device

The results obtained in laboratory tests, using scintillator bars read by silicon photomultipliers are reported. The present approach is the first step for designing a precision tracking system to be placed inside a free magnetized volume for the charge identification of low energy crossing particles. The devised system is demonstrated able to provide a spatial resolution better than 2 mm.

physics.ins-det↗
arXiv2014

The NESSiE way to searches for sterile neutrinos at FNAL

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle $θ_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. Its recent proposal refers to the use of magnetic spectrometers at two different sites, Near and Far ones. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the undergoing project of a multi-site Liquid-Argon detectors at FNAL. The experiment to be possibly setup at Booster will allow to definitively clarify the current $ν_μ$ disappearance tension with $ν_{e}$ appearance and disappearance at the eV mass scale.

hep-ph↗
arXiv2014

The Physics Programme Of The MoEDAL Experiment At The LHC

The MoEDAL experiment at Point 8 of the LHC ring is the seventh and newest LHC experiment. It is dedicated to the search for highly ionizing particle avatars of physics beyond the Standard Model, extending significantly the discovery horizon of the LHC. A MoEDAL discovery would have revolutionary implications for our fundamental understanding of the Microcosm. MoEDAL is an unconventional and largely passive LHC detector comprised of the largest array of Nuclear Track Detector stacks ever deployed at an accelerator, surrounding the intersection region at Point 8 on the LHC ring. Another novel feature is the use of paramagnetic trapping volumes to capture both electrically and magnetically charged highly-ionizing particles predicted in new physics scenarios. It includes an array of TimePix pixel devices for monitoring highly-ionizing particle backgrounds. The main passive elements of the MoEDAL detector do not require a trigger system, electronic readout, or online computerized data acquisition. The aim of this paper is to give an overview of the MoEDAL physics reach, which is largely complementary to the programs of the large multi-purpose LHC detectors ATLAS and CMS.

hep-ph↗