Download or read book The Qweak Experiment A Search for New Physics at the TeV Scale written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new precision measurement of the parity violating analyzing power in longitudinally polarized electron scattering from the proton at very low Q^2 at an incident energy of 1.16 GeV is in the final stages of preparation for execution at Jefferson Laboratory (JLab). A 2200 hour measurement of the parity violating asymmetry in elastic electron-proton scattering at Q^2 = 0.03 (GeV/c)^2 employing 180 microamp of 85% polarized beam on a 0.35 m long liquid hydrogen target will determine the weak charge of the proton, Q_w = 1 - 4sin^2(theta_W), with 4% combined statistical and systematic errors. The Standard Model makes a firm prediction of Q_w, based on the 'running' of the weak mixing angle sin^2(theta_W) from the Z-pole down to lower energies. Any significant deviation of sin^2(theta_W) from its Standard Model prediction at low Q^2 would constitute a signal of new physics. In the absence of new physics, the envisaged experiment will provide a 0.3% determination of sin^2(theta_W), making this a very competitive measurement of the weak mixing angle. Complementary to the present experiment is a measurement of the weak charge of the electron in parity violating Moller scattering at 11 GeV, currently under consideration, with the upgraded CEBAF at JLab. The objective of that experiment would be a measurement of sin2(theta_W) with a precision comparable to or better than any individual measurement at the Z-pole.
Download or read book The Qweak Experiment written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new precision measurement of parity violation in electron scattering from the proton at very low Q2 and forward angles is being prepared for execution at Jefferson Laboratory (JLab). The experiment is a direct challenge to the predictions of the Standard Model of quarks and leptons and is a search for new physics. There exists a unique opportunity to carry out the first precision measurement of the weak charge of the proton, View the MathML source, by building on technical advances that have been made at Jefferson Laboratory's world-leading parity violating electron scattering program and by using the results of earlier experiments to constrain hadronic corrections. A 2200 hour measurement of the parity violating asymmetry in elastic electron-proton scattering at Q2=0.03 (GeV/c)2 employing 180?A of 85% polarized beam on a 0.35 m long liquid hydrogen target will determine the proton's weak charge with 4% combined statistical and systematic errors. The Standard Model makes a firm pre.
Download or read book The Qweak Experiment at Jefferson Lab A Search for New Physics at the TeV Scale written by and published by . This book was released on 2009 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Qweak collaboration will make the first precision determination of the proton's weak charge, QWP = 1-4 sin2 thetaw, from a measurement of the parity-violating asymmetry in elastic electron-proton scattering at very low momentum transfer. The results will determine the proton's weak charge with a 4% total error. The Standard Model makes a firm prediction of QWP, based on the running of the weak mixing angle, sin2 thetaw, from the Z0 pole down to low energies, corresponding to a 10sigma effect in this experiment. Any significant deviation of sin2 thetaw from the Standard Model prediction at low Q2 would be a signal of new physics, wheras agreement would place new and significant constraints on possible Standard Model extensions at the TeV mass scale.
Download or read book The Qweak Experiment A Search for New Physics at the TeV Scale by Measurement of the Proton s Weak Charge written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: From a distance, the proton's weak charge is seen through the distorting effects of clouds of virtual particles. The effective weak charge can be calculated by starting with the measured weak coupling at the Z-pole and "running" the coupling to lower energy or, equivalently, longer distances. Because the "electroweak radiative corrections" or "loop diagrams" which give rise to the running depend not only on known particles, but on particles which have not yet been discovered, a difference between the calculated and measured weak charges may signal new physics. A measurement of Qweak to 4% will be sensitive to new physics at the few TeV scale. The Qweak experiment is based on the fact that the parity-violating longitudinal analyzing power, Az, in electron-proton scattering at low momentum transfer and small scattering angle, is proportional to the proton's weak charge. The experiment plans to measure the predicted Az of -0.3 ppm with a combined statistica.
Download or read book The JLab Qweak Proposal A Search for New Physics at the TeV Scale Via a Measurement of the Proton s Weak Charge written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: From a distance, the proton's weak charge is seen through the distorting effects of clouds of virtual particles. The effective weak charge can be calculated by starting with the measured weak coupling at the Z-pole and "running" the coupling to lower energy or, equivalently, longer distances. Because the "electroweak radiative corrections" or "loop diagrams" which give rise to the running depend not only on known particles, but on particles which have not yet been discovered, a difference between the calculated and measured weak charges may signal new physics. A measurement of Qweak to 4% will be sensitive to new physics at the few TeV scale. The Qweak experiment is based on the fact that the parity-violating longitudinal analyzing power, Az, in electron-proton scattering at low momentum transfer and small scattering angle, is proportional to the proton's weak charge. The experiment plans to measure the predicted Az of -0.3 ppm with a combined statistica.
Download or read book A Measurement of the Weak Charge of the Proton Through Parity Violating Electron Scattering Using the Qweak Apparatus written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: After a decade of preparations, the Qweak experiment at Jefferson Lab is making the first direct measurement of the weak charge of the proton, Q^p_W. This quantity is suppressed in the Standard Model making a good candidate for search for new physics beyond the SM at the TeV scale. Operationally, we measure a small (about -0.200 ppm) parity-violating asymmetry in elastic electron-proton scattering in integrating mode while flipping the helicity of the electrons 1000 times per second. Commissioning took place Fall 2010, and we finished taking data in early summer 2012. This dissertation is based on the data taken on an initial two weeks period (Wien0). It will provide an overview of the Qweak apparatus, description of the data acquisition and analysis software systems, and final analysis and results from the Wien0 data set. The result is a 16% measurement of the parity violating electron-proton scattering asymmetry, A = -0.2788 +/- 0.0348 (stat.) +/- 0.0290 (syst.) ppm at Q^2 = 0.0250 +/- 0.0006 (GeV)^2. From this a 21% measurement of the weak charge of the proton, Q_w^p(msr)= +0.0952 +/- 0.0155 (stat.) +/- 0.0131 (syst.) +/- 0.0015 (theory) is extracted. From this a 2% measurement of the weak mixing angle, sin^2theta_W(msr)= +0.2328 +/- 0.0039 (stat.) +/- 0.0033 (syst.) +/- 0.0004 (theory) and improved constraints on isoscalar/isovector effective coupling constants of the weak neutral hadronic currents are extracted. These results deviate from the Standard Model by one standard deviation. The Wien0 results are a proof of principle of the Qweak data analysis and a highlight of the road ahead for obtaining full results.
Download or read book Spin 2004 Proceedings Of The 16th International Spin Physics Symposium And Workshop On Polarized Electron Sources And Polarimeters With Cd rom written by Franco Bradamante and published by World Scientific. This book was released on 2005-08-02 with total page 1065 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive volume covers the most recent advances in the field of spin physics, including the latest research in high energy and nuclear physics and the study of nuclear spin structure. The comprehensive coverage also includes polarized proton and electron acceleration and storage as well as polarized ion sources and targets. Many significant new results and achievements on the different topics considered at the symposium are presented in this book for the first time.
Download or read book Qweak written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low Q[sup 2] of a longitudinally polarized electron beam on a proton target. The experiment will measure the weak charge of the proton, and thus the weak mixing angle at low energy scale, providing a precision test of the Standard Model. Since the value of the weak mixing angle is approximately 1/4, the weak charge of the proton Q[sub w][sup p] = 1-4 sin[sup 2] [theta][sub w] is suppressed in the Standard Model, making it especially sensitive to the value of the mixing angle and also to possible new physics. The experiment is approved to run at JLab, and the construction plan calls for the hardware to be ready to install in Hall C in 2007. The theoretical context of the experiment and the status of its design are discussed.
Download or read book Hadron Structure in Electroweak Precision Measurements written by Nathan L. Hall and published by Springer. This book was released on 2015-07-24 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the γZ box contribution to the weak charge of the proton. Here, by combining recent parity-violating electron-deuteron scattering data with our current understanding of parton distribution functions, the author shows that one can limit this model dependence. The resulting construction is a robust model of the γγ and γZ structure functions that can also be used to study a variety of low-energy phenomena. Two such cases are discussed in this work, namely, the nucleon’s electromagnetic polarizabilities and quark-hadron duality. By using phenomenological information to constrain the input structure functions, this important but previously poorly understood radiative correction is determined at the kinematics of the parity-violating experiment, QWEAK, to a degree of precision more than twice that of the previous best estimate. A detailed investigation into available parametrizations of the electromagnetic and interference cross-sections indicates that earlier analyses suffered from the inability to correctly quantify their model dependence.
Download or read book In Memory Of Vernon Willard Hughes Proceedings Of The Memorial Symposium In Honor Of Vernon Willard Hughes written by Emlyn Willard Hughes and published by World Scientific. This book was released on 2004-12-22 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: On March 25, 2003 Professor Vernon Hughes of Yale University passed away in New Haven, Connecticut. His career in physics extended over more than 50 years, and his highly influential research work contributed invaluably to numerous fundamental questions in physics.This book comprises a compilation of articles covering talks given at the Vernon Willard Hughes Memorial Symposium, which took place at Yale University in November 2003. The fascinating contributions from many leading experimental and theoretical physicists cover topics in atomic, nuclear and particle physics, as well as include remarks made by Professor Alan Bromley at the symposium dinner. The book also features the Biographical Memoirs of Professor Hughes, written by Professor Robert Adair for the US National Academy of Sciences, and a complete list of Professor Hughes's publications.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings® (ISTP® / ISI Proceedings)• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)• CC Proceedings — Engineering & Physical Sciences
Download or read book The Weak Charge of the Proton written by Scott James MacEwan and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Qweak experiment will provide the most precise determination of the proton's weak charge Q^p_W by measuring the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer Q^2 = 0.0250 (GeV/c)^2. Qpw is related to the weak mixing angle sin^2\theta_W, a fundamental parameter of the standard model. A final measurement of the weak charge at the proposed 4% relative uncertainty is sensitive to certain types of new parity-violating physics beyond the standard model at the TeV mass-scale. Data were taken over a two year period beginning in 2010, using a custom apparatus installed in Hall-C at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. A 180 microamp beam of longitudinally polarized electrons was accelerated to 1.165 GeV and then scattered from unpolarized protons in a liquid hydrogen target. The scattered electrons were then collimated and steered using a magnetic spectrometer onto a set of azimuthally symmetric quartz bar Cherenkov detectors. The performance of this main detector subsystem will be described in detail in this dissertation. A blinded analysis of Run-II, roughly 2/3 of the entire Qweak data set, resulted in an elastic ep asymmetry of -235.6 +/- 8.7 (Stat) +/- 9.3 (Syst.) +/- 39.3 (Blind) ppb. Using this value, the proton's weak charge was calculated to be QpW = 0.0714 +/- 0.0093. This constitutes a 17% relative measurement, that will reduce to
Download or read book A Search for New Physics at the TeV Scale Via a Precise Measurement of the Weak Mixing Angle in Moller Scattering written by Waled S. Emam and published by . This book was released on 2004 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 10th Conference on the Intersections of Particle and Nuclear Physics written by Marvin L. Marshak and published by American Institute of Physics. This book was released on 2010-01-11 with total page 1010 pages. Available in PDF, EPUB and Kindle. Book excerpt: CIPANP 2009 explores areas of common interest between nuclear physicists, high energy (particle) physicists and astrophysicists. These areas range from studies of the strong interactions that bind nuclei together to physics of the very early Universe and include such topics as neutrinos, hadron physics, spin physics, heavy ion physics, QCD and heavy flavor physics. The Conference papers include descriptions of searches for "new physics", phenomena that cannot be accounted for by current theories.
Download or read book Searching for New Physics in b sl l Transitions at the LHCb Experiment written by Luca Pescatore and published by Springer. This book was released on 2017-10-04 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents two analyses of semileptonic b → sl+l− decays using Flavour Changing Neutral Currents (FCNCs) to test for the presence of new physics and lepton flavour universality, and the equality of couplings for different leptons, which on the basis of experimental evidence is assumed to hold in the Standard Model, free from uncertainties as a result of knowledge of the hadronic matrix elements. It also includes the angular analysis of Lambda_b->Lambda mumu decay and the RK* measurement, both of which are first measurements, not yet performed by any other experiment.
Download or read book Weak Scale Supersymmetry written by Howard Baer and published by Cambridge University Press. This book was released on 2023-01-31 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: This OA text develops the basic concepts of supersymmetry for experimental and phenomenological particle physicists and graduate students.
Download or read book From Parity Violation to Hadronic Structure and more written by K. de Jager and published by Springer Science & Business Media. This book was released on 2008-06-21 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the third international workshop on From Parity Violation to Hadronic Structure and More. The many applications of parity violation are way beyond the scope of what Lee and Yang could have imagined fifty years after their proposal. For the physics topics discussed during this workshop, the application of parity violation has become a standard work horse allowing for the extraction of many physics topics in different experiments.
Download or read book Theory Meets Experiment Proceedings Of The Johns Hopkins Workshop On Current Problems In Particle Theory 18 written by Roberto Casalbuoni and published by World Scientific. This book was released on 1995-06-29 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The workshop collected together theoreticians and experimentalists for a discussion about the most recent experiments and their impact on theoretical ideas. The discussion included the new data from LEP and SLD, the evidence for the top quark from Tevatron, the structure function measurements from HERA, and the searches for dark matter. Also, new projects for physics with large neutrino detectors and CP violation at e+e- factories were presented, and a survey of high energy astroparticle physics was included. Particular attention was paid to the interplay between microscopical and cosmological scales.
