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9 results on '"Mccann, Michael Andrew"'

1. Maximising the physics potential of $B^\pm\to\pi^\pm\mu^+\mu^-$ decays

Author

Marshall, Alexander Mclean, McCann, Michael Andrew, Patel, Mitesh, Petridis, Konstantinos A., Reboud, Méril, and van Dyk, Danny

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment
Abstract

We present a method that maximises the experimental sensitivity to new physics contributions in $B^\pm\to\pi^\pm\mu^+\mu^-$ decays. This method relies on performing an unbinned maximum likelihood fit to both the measured dimuon $q^2$ distribution of $B^\pm\to\pi^\pm\mu^+\mu^-$ decays, and theory calculations at spacelike $q^2$, where QCD predictions are most reliable. We exploit the known analytic properties of the decay amplitude and employ a dispersion relation to describe the non-local hadronic contributions across spacelike and timelike $q^2$ regions. The fit stability and the sensitivity to new physics couplings and new sources of $CP$-violation are studied for current and future data-taking scenarios, with the LHCb experiment as an example. The proposed method offers a precise and reliable way to search for new physics in these decays.

Published
2023
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2. A complete description of P- and S-wave contributions to the $B^0\to K^{+}\pi^{-}\ell^{+}\ell^{-}$ decay

Author

Algueró, Marcel, Cartelle, Paula Alvarez, Marshall, Alexander Mclean, Masjuan, Pere, Matias, Joaquim, McCann, Michael Andrew, Patel, Mitesh, Petridis, Konstantinos A., and Smith, Mark

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment
Abstract

In this paper we present a detailed study of the four-body decay $B^0\to K^{+}\pi^{-}\ell^{+}\ell^{-}$, where tensions with the Standard Model predictions have been observed. Our analysis of the decay with P- and S-wave contributions to the $K^{+}\pi^{-}$ system develops a complete understanding of the symmetries of the distribution, in the case of massless and massive leptons. In both cases, the symmetries determine relations between the observables in the $B^0\to K^{+}\pi^{-}\ell^{+}\ell^{-}$ decay distribution. This enables us to define the complete set of observables accessible to experiments, including several that have not previously been identified. The new observables arise when the decay rate is written differentially with respect to $m_{K\pi}$. We demonstrate that experiments will be able to fit this full decay distribution with currently available data sets and investigate the sensitivity to new physics scenarios given the experimental precision that is expected in the future. The symmetry relations provide a unique handle to explore the behaviour of S-wave observables by expressing them in terms of P-wave observables, therefore minimising the dependence on poorly-known S-wave form factors. Using this approach, we construct two theoretically clean S-wave observables and explore their sensitivity to new physics. By further exploiting the symmetry relations, we obtain the first bounds on the S-wave observables using two different methods and highlight how these relations may be used as cross-checks of the experimental methodology. We identify a zero-crossing point that would be at a common dilepton invariant mass for a subset of P- and S-wave observables, and explore the information on new physics and hadronic effects that this zero point can provide., Comment: 49 pages, 25 figures

Published
2021
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3. Magnetometery for cryoEDM

Author

McCann, Michael Andrew, Kraus, Hans, and van der Grinten, Maurits

Subjects
538, Particle physics, cryoEDM, nEDM, magnetometry, electric dipole moment
Abstract

The existence of the matter in the universe is still an unsolved puzzle. After the Big Bang, both matter and antimatter should have been created in equal amounts, and subsequently annihilated. The leading theories to explain the existence of matter require an imbalance in the production of matter and antimatter in the early universe. This in turn requires CP violation, an asymmetry of the laws of physics between matter and antimatter. cryoEDM is designed to explore the total amount of CP violation and resolve this issue. cryoEDM is a next-generation neutron electric dipole moment search in a commissioning phase of development at the Institut Laue-Langevin, Grenoble. A critical requirement of EDM searches is knowledge of the magnetic environment. This work is concerned with the development, implementation, and performance of the currently operating magnetometry system based on SQUID magnetometers. An analysis scheme to provide magnetometry data over the volume occupied by the neutrons, from measurements using the available magnetometers, is developed. An updated method to calibrate the magnetometers using internal sources of magnetic fields is presented, and found to give good agreement with independent measurements. A new method of calibration using the neutrons as a reference is discussed, and tests on an example arrangement are shown to be promising. Algorithms for detecting and correcting for hardware induced artefacts in the data are produced, and demonstrated to reconstruct the field with good agreement in all but the noisiest environments. A software framework is developed to combine these into a real-time analysis that provides feedback and diagnostics to the experiment. Using this new system the resolution of the magnetometers installed in cryoEDM is found to be limited by the environmental noise, and would give a false EDM signal that is greater than the statistical uncertainty in neutron counting. However, the resolution has been somewhat artificially limited to reduce the susceptibility to the RF interference present. This still allows the magnetometry to act as a useful diagnostic tool on any issues in the current magnetic environment, even if in a sub-optimal configuration. For example, investigation of the magnetic shielding of the experiment finds a reduction in the shielding relative to the design, a situation which is being addressed with the design of additional shielding. Once this shielding is installed the resolution of the magnetometers will improve as well as the slew rate of the SQUIDs, which is found to be lower than the $47,mu extup{Ts}^{-1}$ required to measure AC fields applied during a measurement. The current system can also determine sources of magnetic perturbations created within the experiment, which will require addressing before a full EDM run can be performed. For example, cryogenic effects are observed to occur approximately hourly causing large shifts in the magnetic field. Also operation of valves controlling the flow of neutrons around the experiment are found to produce both AC magnetic fields from the driving motors, and shifts in the field from their movement. Situations which can be resolved by reexamination of installation and operational procedures.

Published
2012

6. A complete description of P- and S-wave contributions to the B0 → K+π−ℓ+ℓ− decay.

Author

Algueró, Marcel, Cartelle, Paula Alvarez, Marshall, Alexander Mclean, Masjuan, Pere, Matias, Joaquim, McCann, Michael Andrew, Patel, Mitesh, Petridis, Konstantinos A., and Smith, Mark

Abstract

In this paper we present a detailed study of the four-body decay B0 → K+π−ℓ+ℓ−, where tensions with the Standard Model predictions have been observed. Our analysis of the decay with P- and S-wave contributions to the K+π− system develops a complete understanding of the symmetries of the distribution, in the case of massless and massive leptons. In both cases, the symmetries determine relations between the observables in the B0 → K+π−ℓ+ℓ− decay distribution. This enables us to define the complete set of observables accessible to experiments, including several that have not previously been identified. The new observables arise when the decay rate is written differentially with respect to m K π . We demonstrate that experiments will be able to fit this full decay distribution with currently available data sets and investigate the sensitivity to new physics scenarios given the experimental precision that is expected in the future. The symmetry relations provide a unique handle to explore the behaviour of S-wave observables by expressing them in terms of P-wave observables, therefore minimising the dependence on poorly-known S-wave form factors. Using this approach, we construct two theoretically optimized S-wave observables and explore their sensitivity to new physics. By further exploiting the symmetry relations, we obtain the first bounds on the S-wave observables using two different methods and highlight how these relations may be used as cross-checks of the experimental methodology and the parametrization of the B0 → K+π−ℓ+ℓ− differential decay rate. We identify a zero-crossing point that would be at a common dilepton invariant mass for a subset of P- and S-wave observables, and explore the information on new physics and hadronic effects that this zero point can provide. [ABSTRACT FROM AUTHOR]

Published
2021
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7. LHCb Upgraded RICH 1 Engineering Design Review Report

Author

Adinolfi, Marco, Kariuki, James Mwangi, Petridis, Konstantinos, Rademacker, Jonas, Garsed, Philip John, Wotton, Stephen, Cardinale, Roberta, Petrolini, Alessandro, Clark, David Edward, Egede, Ulrik, Mccann, Michael Andrew, Patel, Mitesh, Savidge, Trevor Edward, Websdale, David, Brock, Matthew, Harnew, Neville, Tacon, M, Benettoni, Massimo, Brummitt, Amanda Jayne, Easo, Sajan, Papanestis, Antonis, Ricciardi, Stefania, Wilson, Fergus, D'ambrosio, Carmelo, Frei, Christoph, He, jibo, and Piedigrossi, Didier

Subjects
Physics::Instrumentation and Detectors, Detectors and Experimental Techniques
Abstract

During the Long Shutdown 2 of the LHC, the LHCb collaboration will replace the upstream Ring Imaging Cherenkov detector (RICH 1). The magnetic shield of the current RICH 1 will be modified, new spherical and plane mirrors will be installed and a new gas enclosure will be manufactured. New photon detectors (multianode photomultiplier tubes) will be used and these, together with their readout electronics, require a new mechanical support system. This document describes the new optical arrangement of RICH 1, its engineering design, installation and alignment. A summary of the project schedule and institute responsibilities is provided.

Published
2016

9. LHCb Summary

Author

Mccann, Michael Andrew

Subjects
Talk
Published
2016

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