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Full-Text Articles in Physics

Search For Pair Production Of Second-Generation Scalar Leptoquarks In Pp Collisions At √S= 7 Tev, V. Khachatryan, A. M. Sirunyan, Thomas Bergauer, Marc M. Baarmand, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov, B. Dorney, S. Guragain May 2011

Search For Pair Production Of Second-Generation Scalar Leptoquarks In Pp Collisions At √S= 7 Tev, V. Khachatryan, A. M. Sirunyan, Thomas Bergauer, Marc M. Baarmand, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov, B. Dorney, S. Guragain

Aerospace, Physics, and Space Science Faculty Publications

A search for pair production of second-generation scalar leptoquarks in the final state with two muons and two jets is performed using proton-proton collision data at ffiffi s p ¼ 7 TeV collected by the CMS detector at the LHC. The data sample used corresponds to an integrated luminosity of 34 pb 1. The number of observed events is in good agreement with the predictions from the standard model processes. An upper limit is set on the second-generation leptoquark cross section times 2 as a function of the leptoquark mass, and leptoquarks with masses below 394 GeV are excluded at …


Search For Pair Production Of Second-Generation Scalar Leptoquarks In Pp Collisions At √S = 7 Tev, V. Khachatryan, A. M. Sirunyan, Thomas Bergauer, Marc M. Baarmand, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov, B. Dorney, S. Guragain May 2011

Search For Pair Production Of Second-Generation Scalar Leptoquarks In Pp Collisions At √S = 7 Tev, V. Khachatryan, A. M. Sirunyan, Thomas Bergauer, Marc M. Baarmand, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov, B. Dorney, S. Guragain

Aerospace, Physics, and Space Science Faculty Publications

A search for pair production of second-generation scalar leptoquarks in the final state with two muons and two jets is performed using proton-proton collision data at ffiffi s p ¼ 7 TeV collected by the CMS detector at the LHC. The data sample used corresponds to an integrated luminosity of 34 pb 1. The number of observed events is in good agreement with the predictions from the standard model processes. An upper limit is set on the second-generation leptoquark cross section times 2 as a function of the leptoquark mass, and leptoquarks with masses below 394 GeV are excluded at …


Hydrogen-Deuterium Isotope Shift: From The 1s-2s-Transition Frequency To The Proton-Deuteron Charge-Radius Difference, Ulrich D. Jentschura, Arthur N. Matveev, Christian G. Parthey, Janis Alnis, Randolf Pohl, Th H. Udem, Nikolai N. Kolachevsky, Theodor Wolfgang Hansch Apr 2011

Hydrogen-Deuterium Isotope Shift: From The 1s-2s-Transition Frequency To The Proton-Deuteron Charge-Radius Difference, Ulrich D. Jentschura, Arthur N. Matveev, Christian G. Parthey, Janis Alnis, Randolf Pohl, Th H. Udem, Nikolai N. Kolachevsky, Theodor Wolfgang Hansch

Physics Faculty Research & Creative Works

We analyze and review the theory of the hydrogen-deuterium isotope shift for the 1S-2S transition, which is one of the most accurately measured isotope shifts in any atomic system, in view of a recently improved experiment. A tabulation of all physical effects that contribute to the isotope shift is given. These include the Dirac binding energy, quantum electrodynamic effects, including recoil corrections, and the nuclear-size effect, including the pertaining relativistic and radiative corrections. From a comparison of the theoretical result Δfth=670999566.90(66)(60)kHz (exclusive of the nonrelativistic nuclear-finite-size correction) and the experimental result Δfexpt=670994334605(15) Hz, we infer the …


Differential Cross Sections For Single Ionization Of H₂ By 75-Kev Proton Impact, Ujjal Chowdhury, Michael Schulz, Don H. Madison Mar 2011

Differential Cross Sections For Single Ionization Of H₂ By 75-Kev Proton Impact, Ujjal Chowdhury, Michael Schulz, Don H. Madison

Physics Faculty Research & Creative Works

We have calculated triply differential cross sections (TDCS) and doubly differential cross sections (DDCS) for single ionization of H2 by 75-keV proton impact using the molecular three-body distorted-wave-eikonal initial-state (M3DW-EIS) approach. Previously published measured DDCS (differential in the projectile scattering angle and integrated over the ejected electron angles) found pronounced structures at relatively large angles that were interpreted as an interference resulting from the two-centered potential of the molecule. Theory treating H2 as atomic H multiplied by a molecular interference factor only predicts the observed structure when assumptions are made about the molecular orientation. Here we apply the …


Scattering-Angle Dependence Of Doubly Differential Cross Sections For Fragmentation Of H₂ By Proton Impact, Kisra N. Egodapitiya, Sachin D. Sharma, Aaron C. Laforge, Michael Schulz Jan 2011

Scattering-Angle Dependence Of Doubly Differential Cross Sections For Fragmentation Of H₂ By Proton Impact, Kisra N. Egodapitiya, Sachin D. Sharma, Aaron C. Laforge, Michael Schulz

Physics Faculty Research & Creative Works

We have measured double differential cross sections (DDCS) for proton fragment formation for fixed projectile energy losses as a function of projectile scattering angle in 75 keV p + H2 collisions. An oscillating pattern was observed in the angular dependence of the DDCS with a frequency about twice as large as what we found earlier for nondissociative ionization. Possible origins for this frequency doubling are discussed.