V. Popa

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 multipurpose LHC detectors ATLAS and CMS.

Calibration with relativistic and low-velocity ions of a CR39 nuclear track detector

SummaryWe present experimental results on the calibration of the CR39 nuclear track detector, manufactured by the Intercast Europe Co., of Parma (Italy). The calibration was performed with several ions of different kinetic energies: from 50 keV protons to 11.3A GeV gold ions; β=v/c ranges from about 4·10−3 to about 1. We find that a single curve of the reduced etch ratep vs. restricted energy loss is able to describe all data. Furthermore the data are consistent with about 100% contribution of the nuclear energy loss to the CR39 response. This type of CR39 is used in the MACRO experiment at the Gran Sasso Laboratory.

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

A bstractThe 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 nucleartrack detectors with surface area ~18m2, 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 8TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb–1. No magnetic charge exceeding 0:5gD (where gD 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≤ m ≤ 3500 GeV. Model-independent cross-section limits are presented in fiducial regions of monopole energy and direction for 1gD ≤ |g| ≤ 6gD, and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for 1gD ≤ |g| ≤ 4gD. Under the assumption of Drell-Yan cross sections, mass limits are derived for |g| = 2gD and |g| = 3gD for the first time at the LHC, surpassing the results from previous collider experiments.

Calibration with relativistic and low velocity ions of a CR39 nuclear track detector

Abstract We present experimental results on the calibration of the CR9 nuclear track detector, manufactured by the Intercast Europe Co., of Parma (Italy). The calibration was performed with several ions of different kinetic energies: from 50 keV protons to 11.3 A GeV gold ions; β =v/c ranges from about 4·10 −3 to about 1. We find that a single curve of the reduced etch rate p versus Restricted Energy Loss is able to describe all data. Furthermore the data are consistent with about 100% contribution of the nuclear energy loss to the CR39 response. This type of CR39 is used in the MACRO experiment at the Gran Sasso Laboratory.

Search for possible neutrino radiative decays during the 2001 total solar eclipse

Abstract We present the results of the observations performed in the occasion of the 21st June 2001 total solar eclipse, looking for visible photons emitted through a possible radiative decay of solar neutrinos. We establish lower limits for the ν2 or ν3 proper lifetimes τ0/m⩾103 s/eV, for neutrino masses larger than 10−2 eV.

Monte Carlo simulation of an experiment looking for radiative solar neutrino decays

Abstract We analyse the possibility of detecting visible photons from a hypothetical radiative decay of solar neutrinos. Our study is focused on the simulation of such measurements during total solar eclipses and it is based on the BP2000 Standard Solar Model and on the most recent experimental information concerning the neutrino properties. Our calculations yield the probabilities of the decays, the shapes of the visible signals and the spectral distributions of the expected photons, under the assumption that solar neutrino oscillations occur according to the LMA model.

Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb−1 of 13 TeV proton–proton collisions at the LHC

Abstract 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.