23 research outputs found

    SEARCH FOR CPT AND LORENTZ INVARIANCE VIOLATION IN THE MUON g-2 EXPERIMENT AT FERMILAB

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    The Muon g-2 experiment at Fermilab (E989) aims to measure the anomalous magnetic moment of the muon, aμ=(g2)/2a_{\mu}= (g-2)/2, to a groundbreaking precision of 140140 ppb, obtaining a near four-fold increase in precision over the previous experiment, E821, at the Brookhaven National Laboratory (BNL). The value of aμa_{\mu} from BNL currently differs from the Standard Model prediction by 3.7\sim 3.7 standard deviations, suggesting the potential for new physics and therefore, motivating a new experiment.Because the theory predicts this number with high precision, testing the g-factor through experiment provides a stringent test of the SM and can suggest physics beyond the Standard Model. The goal of the Fermilab Muon g2g-2 experiment is to increase the statistical precision by more than a factor of 20 and reduce systematic errors by a factor of 3. By measuring muon precession rate (ωa\omega_a) in an external magnetic field, the anomalous magnetic moment will be calculated. This is an incredibly challenging experiment with a unique opportunity to provide new insight into nature. \\ The g2g-2 data also provides a great opportunity for setting the most stringent limits on some of the Standard Model Extension CPT Lorentz violating (LV) parameters in the muon sector. One of the CPT and Lorentz violating signatures that we can look for using g2g-2 data is a sidereal variation of ωa(t)\omega_a(t). Extensive simulation studies confirm that the sensitivity regarding the sidereal varation roughly scales with ωa\omega_a uncertainty. Hence, the g2g-2 experiment at FNAL should be able to reach limits of 5×1025\sim 5\times10^{-25} GeV. Because the CPT and LV analyses are essentially studies of variations in ωa\omega_a as a function of time and charge, performing an ωa\omega_a analysis sets the stage for the CPT and LV measurement. This dissertation focuses on the methodology of a fully functioning framework and analyzing the Fermilab Muon g2g - 2 Run 2 data containing 11\sim 11 billion events above an energy threshold of 1.71.7~GeV

    Measurement of electrical properties of electrode materials for the bakelite Resistive Plate Chambers

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    Single gap (gas gap 2 mm) bakelite Resistive Plate Chamber (RPC) modules of various sizes from 10 cm \times 10 cm to 1 m \times 1 m have been fabricated, characterized and optimized for efficiency and time resolution. Thin layers of different grades of silicone compound are applied to the inner electrode surfaces to make them smooth and also to reduce the surface resistivity. In the silicone coated RPCs an efficiency > 90% and time resolution \sim 2 ns (FWHM) have been obtained for both the streamer and the avalanche mode of operation. Before fabrication of detectors the electrical properties such as bulk resistivity and surface resistivity of the electrode materials are measured carefully. Effectiveness of different silicone coating in modifying the surface resistivity was evaluated by an instrument developed for monitoring the I-V curve of a high resistive surface. The results indicate definite correlation of the detector efficiency for the atmospheric muons and the RPC noise rates with the surface resistivity and its variation with the applied bias voltage. It was also found that the surface resistivity varies for different grades of silicone material applied as coating, and the results are found to be consistent with the detector efficiency and noise rate measurements done with these RPCs.Comment: 9 Pages, 6 figure

    Measurement of electrical properties of electrode materials for the bakelite Resistive Plate Chambers

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    Single gap (gas gap 2 mm) bakelite Resistive Plate Chamber (RPC) modules of various sizes from 10 cm \times 10 cm to 1 m \times 1 m have been fabricated, characterized and optimized for efficiency and time resolution. Thin layers of different grades of silicone compound are applied to the inner electrode surfaces to make them smooth and also to reduce the surface resistivity. In the silicone coated RPCs an efficiency > 90% and time resolution \sim 2 ns (FWHM) have been obtained for both the streamer and the avalanche mode of operation. Before fabrication of detectors the electrical properties such as bulk resistivity and surface resistivity of the electrode materials are measured carefully. Effectiveness of different silicone coating in modifying the surface resistivity was evaluated by an instrument developed for monitoring the I-V curve of a high resistive surface. The results indicate definite correlation of the detector efficiency for the atmospheric muons and the RPC noise rates with the surface resistivity and its variation with the applied bias voltage. It was also found that the surface resistivity varies for different grades of silicone material applied as coating, and the results are found to be consistent with the detector efficiency and noise rate measurements done with these RPCs.Comment: 9 Pages, 6 figure

    Reduction of coherent betatron oscillations in a muon g-2 storage ring experiment using RF fields

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    This work demonstrates that two systematic errors, coherent betatron oscillations (CBO) and muon losses can be reduced through application of radio frequency (RF) electric fields, which ultimately increases the sensitivity of the muon g2g-2 experiments. As the ensemble of polarized muons goes around a weak focusing storage ring, their spin precesses, and when they decay through the weak interaction, μ+e+νeνμˉ\mu^+ \rightarrow e^+ \nu_e \bar{\nu_\mu}, the decay positrons are detected by electromagnetic calorimeters. In addition to the expected exponential decay in the positron time spectrum, the weak decay asymmetry causes a modulation in the number of positrons in a selected energy range at the difference frequency between the spin and cyclotron frequencies, ωa\omega_\text{a}. This frequency is directly proportional to the magnetic anomaly aμ=(g2)/2a_\mu =(g-2)/2, where gg is the g-factor of the muon, which is slightly greater than 2. The detector acceptance depends on the radial position of the muon decay, so the CBO of the muon bunch following injection into the storage ring modulate the measured muon signal with the frequency ωCBO\omega_\text{CBO}. In addition, the muon populations at the edge of the beam hit the walls of the vacuum chamber before decaying, which also affects the signal. Thus, reduction of CBO and unwanted muon loss increases the aμa_\mu measurement sensitivity. Numerical and experimental studies with RF electric fields yield more than a magnitude reduction of the CBO, with muon losses comparable to the conventional method.Comment: 14 pages, 25 figure

    Physics Potential of the ICAL detector at the India-based Neutrino Observatory (INO)

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    The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.Comment: 139 pages, Physics White Paper of the ICAL (INO) Collaboration, Contents identical with the version published in Pramana - J. Physic

    Measurement of electrical properties of electrode materials for the bakelite Resistive Plate Chambers

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    Single gap (gas gap 2 mm) bakelite Resistive Plate Chamber (RPC) modules of various sizes from 10 cm \times 10 cm to 1 m \times 1 m have been fabricated, characterized and optimized for efficiency and time resolution. Thin layers of different grades of silicone compound are applied to the inner electrode surfaces to make them smooth and also to reduce the surface resistivity. In the silicone coated RPCs an efficiency > 90% and time resolution \sim 2 ns (FWHM) have been obtained for both the streamer and the avalanche mode of operation. Before fabrication of detectors the electrical properties such as bulk resistivity and surface resistivity of the electrode materials are measured carefully. Effectiveness of different silicone coating in modifying the surface resistivity was evaluated by an instrument developed for monitoring the I-V curve of a high resistive surface. The results indicate definite correlation of the detector efficiency for the atmospheric muons and the RPC noise rates with the surface resistivity and its variation with the applied bias voltage. It was also found that the surface resistivity varies for different grades of silicone material applied as coating, and the results are found to be consistent with the detector efficiency and noise rate measurements done with these RPCs.Comment: 9 Pages, 6 figure

    Portability: A Necessary Approach for Future Scientific Software

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    Today's world of scientific software for High Energy Physics (HEP) is powered by x86 code, while the future will be much more reliant on accelerators like GPUs and FPGAs. The portable parallelization strategies (PPS) project of the High Energy Physics Center for Computational Excellence (HEP/CCE) is investigating solutions for portability techniques that will allow the coding of an algorithm once, and the ability to execute it on a variety of hardware products from many vendors, especially including accelerators. We think without these solutions, the scientific success of our experiments and endeavors is in danger, as software development could be expert driven and costly to be able to run on available hardware infrastructure. We think the best solution for the community would be an extension to the C++ standard with a very low entry bar for users, supporting all hardware forms and vendors. We are very far from that ideal though. We argue that in the future, as a community, we need to request and work on portability solutions and strive to reach this ideal

    Green synthesis of silver nanoparticles using Ocimum sanctum Linn. and its antibacterial activity against multidrug resistant Acinetobacter baumannii

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    The biosynthesis of nanoparticles using the green route is an effective strategy in nanotechnology that provides a cost-effective and environmentally friendly alternative to physical and chemical methods. This study aims to prepare an aqueous extract of Ocimum sanctum (O. sanctum)-based silver nanoparticles (AgNPs) through the green route and test their antibacterial activity. The biosynthesized silver nanoparticles were characterised by colour change, UV spectrometric analysis, FTIR, and particle shape and size morphology by SEM and TEM images. The nanoparticles are almost spherical to oval or rod-shaped with smooth surfaces and have a mean particle size in the range of 55 nm with a zeta potential of −2.7 mV. The antibacterial activities of AgNPs evaluated against clinically isolated multidrug-resistant Acinetobacter baumannii (A. baumannii) showed that the AgNPs from O. sanctum are effective in inhibiting A. baumannii growth with a zone of inhibition of 15 mm in the agar well diffusion method and MIC and MBC of 32 µg/mL and 64 µg/mL, respectively. The SEM images of A. baumannii treated with AgNPs revealed damage and rupture in bacterial cells. The time-killing assay by spectrophotometry revealed the time- and dose-dependent killing action of AgNPs against A. baumannii, and the assay at various concentrations and time intervals indicated a statistically significant result in comparison with the positive control colistin at 2 µg/mL (P < 0.05). The cytotoxicity test using the MTT assay protocol showed that prepared nanoparticles of O. sanctum are less toxic against human cell A549. This study opens up a ray of hope to explore the further research in this area and to improve the antimicrobial activities against multidrug resistant bacteria
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