Download or read book Dark Photon Search at BABAR written by and published by . This book was released on 2012 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented is the current progress of a search for the signature of a dark photon or new particle using the BaBar data set. We search for the processes ee− →?{sub ISR}A′, A′ → e+e− and e+e− →?{sub ISR}?,? → A′, A′ → e+e−, where?{sub ISR} is an initial state radiated photon of energy E{sub {gamma}}>= 1 GeV. Twenty-five sets of Monte Carlo, simulating e+e− collisions at an energy of 10.58 GeV, were produced with different values of the A′ mass ranging from 100 MeV to 9.5 GeV. The mass resolution is calculated based on Monte Carlo simulations. We implement ROOT's Toolkit for Multivariate Analysis (TMVA), a machine learning tool that allows us to evaluate the signal character of events based on many of discriminating variables. TMVA training is conducted with samples of Monte Carlo as signal and a small portion of Run 6 as background. The multivariate analysis produces additional cuts to separate signal and background. The signal efficiency and sensitivity are calculated. The analysis will move forward to fit the background and scan the residuals for the narrow resonance peak of a new particle.
Download or read book The Physics of the Dark Photon written by Marco Fabbrichesi and published by Springer Nature. This book was released on 2020-11-23 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about the dark photon which is a new gauge boson whose existence has been conjectured. Due to its interaction with the ordinary, visible photon, such a particle can be experimentally detected via specific signatures. In this book, the authors review the physics of the dark photon from the theoretical and experimental point of view. They discuss the difference between the massive and the massless case, highlighting how the two phenomena arise from the same vector portal between the dark and the visible sector. A review of the cosmological and astrophysical observations is provided, together with the connection to dark matter physics. Then, a perspective on current and future experimental limits on the parameters of the massless and massive dark photon is given, as well as the related bounds on milli-charged fermions. The book is intended for graduate students and young researchers who are embarking on dark photon research, and offers them a clear and up-to-date introduction to the subject.
Download or read book The DarkLight Experiment written by Dustin R. Katzin and published by . This book was released on 2012 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a setup to search for the existence of a massive gauge boson A', the "dark photon," mediating dark matter interactions with coupling strength [alpha]'. In certain models, the A' decays promptly but invisibly and might be discoverable in high luminosity collider experiments. Following a proposed setup by Wojtsekhowski et al. to use the VEPP-3 electron-positron storage ring at the Budker Institute for Nuclear Physics, we study whether an e+ + e- - A'+ -[gamma] signal could be seen over the quantum electrodynamic background. The proposed VEPP-3 setup is sensitive to an A' within the mass range mA = 5-20 MeV. Out of the two backgrounds, e++e- - 3[gamma] and e+ + e- - e+ + e- + [gamma], we find that the former process provides the dominant background for the A' signal. While positron bremsstrahlung events can be detected and suppressed in Wojtsekhowski's apparatus, the 3[gamma] cross-section has a large cross section in this range, "faking" an A'. We use Monte Carlo numerical integration techniques to calculate the cross sections and obtain reach plots, determining which values of mA' and a' could be discovered at 5[sigma] confidence. This background study can be used to improve the VEPP-3 proposal, and provides a valuable comparison study with the MIT-led DarkLight proposal to search for a dark photon in the same mass range.
Download or read book APEX A Experiment written by John Thomas Austin Williamson and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dark Photon Searches at Future E e Colliders written by Sepideh Hosseini-Senvan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Dark Matter Dark Photon and Z Boson written by Shihao Wu and published by . This book was released on 2014 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Search for Dark Photons at LHCb and Machine Learning in Particle Physics written by Constantin Niko Weisser and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigating hypothetical particles called dark photons helps shed light on the nature of dark matter, which is one of the biggest open questions in particle physics. This thesis presents world-leading limits in searches for prompt-like and long-lived dark photons decaying into two muons, as well as other dimuon resonances, produced in proton-proton collisions and collected by the LHCb experiment at the Large Hadron Collider at CERN.
Download or read book Search for Dark Photons from Supersymmetric Hidden Valleys written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Dark Gauge Bosons Decaying Into Displaced Lepton Jets in Proton proton Collisions at 13 TeV with the ATLAS Detector written by Miriam Deborah Joy Diamond and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The dark photon ($A'$), the gauge boson carrier of a hypothetical new force, has been proposed in a wide range of Beyond the Standard Model (BSM) theories, and could serve as our window to an entire dark sector. A massive $A'$ could decay back to the Standard Model (SM) with a significant branching fraction, through kinetic mixing with the SM photon. If this $A'$ can be produced from decays of a dark scalar that mixes with the SM Higgs boson, collider searches involving leptonic final states provide promising discovery prospects with rich phenomenology. This work presents the results of a search for dark photons in the mass range $0.2 \lesssim m_{A'} \lesssim 10$ GeV decaying into collimated jets of light leptons and mesons, so-called ``lepton-jets". It employs 3.57 \fb of data from protonâ -proton collisions at a centre-of-mass energy of $\sqrt{s} =13$ TeV, collected during 2015 with the ATLAS detector at the LHC. No deviations from SM expectations are observed. Limits on benchmark models predicting Higgs boson decays to $A'$s are derived as a function of the $A'$ lifetime; limits are also established in the parameter space of $m_{A'}$ vs. kinetic mixing parameter $\epsilon$ . These extend the limits obtained in a similar search previously performed during Run 1 of the LHC, to include dark photon masses $2 \lesssim m_{A'} \lesssim 10$ GeV and to cover higher $\epsilon$ values for $0.2 \lesssim m_{A'} \lesssim 2$ GeV, and are complementary to various other ATLAS $A'$ searches. As data-taking continues at the LHC, the reach of lepton-jet analyses will continue to expand in model coverage and in parameter space.
Download or read book The Physics of the Dark Photon written by Marco Fabbrichesi and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about the dark photon which is a new gauge boson whose existence has been conjectured. Due to its interaction with the ordinary, visible photon, such a particle can be experimentally detected via specific signatures. In this book, the authors review the physics of the dark photon from the theoretical and experimental point of view. They discuss the difference between the massive and the massless case, highlighting how the two phenomena arise from the same vector portal between the dark and the visible sector. A review of the cosmological and astrophysical observations is provided, together with the connection to dark matter physics. Then, a perspective on current and future experimental limits on the parameters of the massless and massive dark photon is given, as well as the related bounds on milli-charged fermions. The book is intended for graduate students and young researchers who are embarking on dark photon research, and offers them a clear and up-to-date introduction to the subject.
Download or read book The Anomalous Magnetic Moment of the Muon written by Fred Jegerlehner and published by Springer Science & Business Media. This book was released on 2008 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations.
Download or read book Probing Dark Forces and Light Hidden Sectors at Low Energy E e Colliders written by and published by . This book was released on 2009 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: A dark sector - a new non-Abelian gauge group Higgsed or confined near the GeV scale - can be spectacularly probed in low-energy ee− collisions. A low-mass dark sector can explain the annual modulation signal reported by DAMA/LIBRA and the PAMELA, ATIC, and INTEGRAL observations by generating small mass splittings and new interactions for weak-scale dark matter. Some of these observations may be the first signs of a low-mass dark sector that collider searches can definitively confirm. Production and decay of [Omicron](GeV)-mass dark states is mediated by a Higgsed Abelian gauge boson that mixes kinetically with hypercharge. Existing data from BaBar, BELLE, CLEO-c, and KLOE may contain thousands of striking dark-sector events with a high multiplicity of leptons that reconstruct mass resonances and possibly displaced vertices. We discuss the production and decay phenomenology of Higgsed and confined dark sectors and propose ee− collider search strategies. We also use the DAMA/LIBRA signal to estimate the production cross-sections and decay lifetimes for dark-sector states.
Download or read book Search for Heavy Long lived Particles that Decay to Photons in p bar p Collisions at sqrt s written by and published by . This book was released on 2007 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the results of the first search for heavy, neutral, longlived particles that decay to photons at a hadron collider. We use a sample of +jet+missing transverse energy events in $p \bar{p}$ collisions at √s = 1.96 TeV taken with the Collider Detector at Fermilab. Candidate events are selected based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed. The final result is that we find 2 events, using 570±34 pb-1 of data collected during 2004-2005 at the Fermilab Tevatron, consistent with the background estimate of 1.3±0.7 events. While our search strategy does not rely on model-specific dynamics, we interpret this result in terms of cross section limits in a supersymmetric model with $\vec{X}$$0\atop{1}$ eG and set a world-best e 01 mass reach of 101 GeV/c2 at e = 5 ns. We can exclude any [gamma]+jet+missing transverse energy signal that would produce more than 5.5 events.
Download or read book Dynamics of the Standard Model written by John F. Donoghue and published by Cambridge University Press. This book was released on 2023-01-31 with total page 599 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 2014 edition, now OA, provides a detailed and practical account of the Standard Model of particle physics.
Download or read book Particle Dark Matter written by Gianfranco Bertone and published by Cambridge University Press. This book was released on 2010-01-07 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the dark matter problem in particle physics, astrophysics and cosmology for graduate students and researchers.
Download or read book Search for High Mass Photon Pairs in P anti P Collisions At radical written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present results of a search for diphoton resonances produced inclusively and in association with a vector boson using 100 pb[sup[minus]1] of p[anti p] collisions using the CDF detector. They set upper limits on the product of cross section times branching ratio for p[anti p][r-arrow][gamma][gamma][r-arrow] X and p[anti p][r-arrow][gamma][gamma][r-arrow] W/Z. Using a NLO prediction for associated production cross section of a Higgs with a vector boson (W or Z), they set an upper limit on the branching ratio for H[r-arrow][gamma][gamma]. They set a lower limit on the mass of a'bosophilic' Higgs boson (e.g. one which couples only to[gamma], W, and Z bosons with Standard Model couplings) of 82 GeV/c[sup 2] at 95% C.L.
Download or read book Yet Another Introduction to Dark Matter written by Martin Bauer and published by Springer. This book was released on 2019-06-11 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter is a frequently discussed topic in contemporary particle physics. Written strictly in the language of particle physics and quantum field theory, these course-based lecture notes focus on a set of standard calculations that students need in order to understand weakly interacting dark matter candidates. After introducing some general features of these dark matter agents and their main competitors, the Higgs portal scalar and supersymmetric neutralinos are introduced as our default models. In turn, this serves as a basis for exploring four experimental aspects: the dark matter relic density extracted from the cosmic microwave background; indirect detection including the Fermi galactic center excess; direct detection; and collider searches. Alternative approaches, like an effective theory of dark matter and simplified models, naturally follow from the discussions of these four experimental directions.
