Open Access. Powered by Scholars. Published by Universities.®

Elementary Particles and Fields and String Theory Commons™

Open Access. Powered by Scholars. Published by Universities.®

Quantum Physics

Institution
Keyword
Publication Year
Publication
Publication Type

Articles 181 - 210 of 258

Full-Text Articles in Elementary Particles and Fields and String Theory

Light Vs. Quantum Gravity, Irving Martinez^* Apr 2012

Light Vs. Quantum Gravity, Irving Martinez^*

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Go to article

Photon Impact Factor And š‘˜T Factorization In The Next-To-Leading Order, Ian Balitsky Jan 2012

Photon Impact Factor And š‘˜T Factorization In The Next-To-Leading Order, Ian Balitsky

Physics Faculty Publications

The photon impact factor for the BFKL pomeron is calculated in the next-to-leading order (NLO) approximation using the operator expansion in Wilson lines. The result is represented as a NLO kT-factorization formula for the structure functions of small-x deep inelastic scattering.

Go to article

Measurement Of Exclusive Ī Āŗ Electroproduction Structure Functions And Their Relationship To Transverse Generalized Parton Distributions, Clas Collaboration, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, S. Koirala, S. E. Kuhn, M. Mayer, L. B. Weinstein, I. Bedlinsky, V. Kubarovsky Jan 2012

Measurement Of Exclusive Ī Āŗ Electroproduction Structure Functions And Their Relationship To Transverse Generalized Parton Distributions, Clas Collaboration, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, S. Koirala, S. E. Kuhn, M. Mayer, L. B. Weinstein, I. Bedlinsky, V. Kubarovsky

Physics Faculty Publications

Exclusive Ļ€0 electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in Q2, xB , t , and Ļ•Ļ€ , in the Q2 range from 1.0 to 4.6ā€‰ā€‰GeV2 , āˆ’t up to 2ā€‰ā€‰GeV2 , and xB from 0.1 to 0.58. Structure functions ĻƒT+ĻµĻƒL , ĻƒTT , and ĻƒLT were extracted as functions of t for each of 17 combinations of Q2 and xB . ā€¦

Go to article

Measurement Of The Generalized Form Factors Near Threshold Via Ė *Pā†’NĻ€+ At High QĀ², Clas Collaboration, K. Park, R. W. Gothe, K. P. Adhikari, D. Adikaram, R. P. Bennett, C. E. Hyde, A. Klein, S. E. Kuhn, H. Seraydaryan Jan 2012

Measurement Of The Generalized Form Factors Near Threshold Via Ė *Pā†’NĻ€+ At High QĀ², Clas Collaboration, K. Park, R. W. Gothe, K. P. Adhikari, D. Adikaram, R. P. Bennett, C. E. Hyde, A. Klein, S. E. Kuhn, H. Seraydaryan

Physics Faculty Publications

We report on the first measurement of the F2 structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ā‰² 100ā€‰ā€‰MeV/c and their angles to ā‰³ 100Ā° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The Fn2 data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65 < Q2 2, with uncertainties from nuclear corrections estimated to be less ā€¦

Go to article

Mellin Representation Of The Graviton Bulk-To-Bulk Propagator In Ads Space, Ian Balitsky Jan 2011

Mellin Representation Of The Graviton Bulk-To-Bulk Propagator In Ads Space, Ian Balitsky

Physics Faculty Publications

A Mellin-type representation of the graviton bulk-to-bulk propagator from E. Dā€™Hoker, D.ā€‰Z. Freedman, S.ā€‰D. Mathur, A. Matusis, and L. Rastelli [Nucl. Phys. B562, 330 (1999)] in terms of the integral over the product of bulk-to-boundary propagators is derived.

Go to article

Evolution Of Conformal Color Dipoles And High Energy Amplitudes In š’© = 4 Sym, Ian Balitsky Jan 2011

Evolution Of Conformal Color Dipoles And High Energy Amplitudes In š’© = 4 Sym, Ian Balitsky

Physics Faculty Publications

The high-energy behavior of the š’© = 4 SYM amplitudes in the Regge limit can be calculated order by order in perturbation theory using the high-energy operator expansion in Wilson lines. At large Nc, a typical four-point amplitude is determined by a single BFKL pomeron. The conformal structure of the four-point amplitude is fixed in terms of two functions: pomeron intercept and the coefficient function in front of the pomeron (the product of two residues). The pomeron intercept is universal while the coefficient function depends on the correlator in question. The intercept is known in the first two ā€¦

Go to article

Coherent Photoproduction Of Ī + From 3He, K. P. Adhikari, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, F. SabatiĆ©, L. B. Weinstein, Et Al., The Clas Collaboration Jan 2011

Coherent Photoproduction Of Ī + From 3He, K. P. Adhikari, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, F. SabatiĆ©, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

We have measured the differential cross section for the š›¾ 3He ā†’ Ļ€+t reaction. This reaction was studied using the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid 3He target. The differential cross sections for the š›¾ 3He ā†’ Ļ€+t reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at ā€¦

Go to article

Experimental Results In Dis, Sidis And Des From Jefferson Lab, Sebastian E. Kuhn Jan 2011

Experimental Results In Dis, Sidis And Des From Jefferson Lab, Sebastian E. Kuhn

Physics Faculty Publications

Jefferson Labā€™s electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scatteringā€”DISā€”at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentumā€dependent (TMD) structure functions using Semiā€Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway, a significantly larger kinematic ā€¦

Go to article

High-Energy Amplitudes In The Next-To-Leading Order, Ian Balitsky Jan 2011

High-Energy Amplitudes In The Next-To-Leading Order, Ian Balitsky

Physics Faculty Publications

High-energy scattering in the saturation region is described by the evolution of color dipoles. In the leading order this evolution is governed by the non-linear BK equation. To see if this equation is relevant for existing or future accelerators (like EIC or LHeC) one needs to know how big are the next-to-leading order (NLO) corrections. I review the calculation of the NLO corrections to high-energy amplitudes in QCD.

Go to article

Search For The Photoexcitation Of Exotic Mesons In The Ī +Ī +Ī - System, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, S. Bektasoglu, S. BĆ¼ltmann, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, L. M. Qin, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2009

Search For The Photoexcitation Of Exotic Mesons In The Ī +Ī +Ī - System, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, S. Bektasoglu, S. BĆ¼ltmann, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, L. M. Qin, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

A search for exotic mesons in the Ļ€+Ļ€+Ļ€āˆ’ system photoproduced by the charge exchange reaction Ī³pā†’Ļ€+Ļ€+Ļ€āˆ’(n) was carried out by the CLAS Collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A partial wave analysis was performed on a sample of 83ā€‰000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the ā€¦

Go to article

Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, Clas Collaboration, K. P. Adhikari, S. L. Careccia, T. A. Forest, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan Jan 2009

Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, Clas Collaboration, K. P. Adhikari, S. L. Careccia, T. A. Forest, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan

Physics Faculty Publications

We present results on the electroexcitation of the low mass resonances Ī”(1232)P33 , N(1440)P11 , N(1520)D13 , and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for Ļ€ electroproduction off the proton. The data were analyzed using two conceptually different approachesā€”fixed-t dispersion relations and a unitary isobar modelā€”allowing us to ā€¦

Go to article

Measurement Of Semi-Inclusive Ī + Electroproduction Off The Proton, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. BĆ¼ltmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, L. M. Qin, L. B. Weinstein, J. Zhang Jan 2009

Measurement Of Semi-Inclusive Ī + Electroproduction Off The Proton, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. BĆ¼ltmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, L. M. Qin, L. B. Weinstein, J. Zhang

Physics Faculty Publications

Semi-inclusive Ļ€+ electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range including the complete range of azimuthal angles between hadronic and leptonic planes, Ļ• , enabling us to separate the Ļ•-dependent terms. Our measurements of the Ļ• -independent term of the cross section at low Bjorken x were found to be in fairly good agreement with pQCD calculations. Indeed, the conventional current fragmentation calculation can account for almost all ā€¦

Go to article

Photodisintegration Of 4He Into P+T, Clas Collaboration, M. J. Amaryan, S. L. Careccia, G. E. Dodge, C. E. Hyde, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan, S. Tkachenko, L.B. Weinstein, J. Zhang Jan 2009

Photodisintegration Of 4He Into P+T, Clas Collaboration, M. J. Amaryan, S. L. Careccia, G. E. Dodge, C. E. Hyde, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan, S. Tkachenko, L.B. Weinstein, J. Zhang

Physics Faculty Publications

The two-body photodisintegration of 4He into a proton and a triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Real photons produced with the Hall-B bremsstrahlung-tagging system in the energy range from 0.35 to 1.55 GeV were incident on a liquid 4He target. This is the first measurement of the photodisintegration of 4He above 0.4 GeV. The differential cross sections for the Ī³ 4He ā†’pt reaction were measured as a function of photon-beam energy and proton-scattering angle and are compared with the latest model calculations by J.-M. Laget. At ā€¦

Go to article

Measurement Of The Differential Cross Section For The Reaction Ī“n ā†’Ī ā»P From Deuterium, M. J. Amaryan, H. Badasaryan, S. L. Careccia, G. E. Dodge, C. E. Hyde, S. E. Kuhn, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration Jan 2009

Measurement Of The Differential Cross Section For The Reaction Ī“n ā†’Ī ā»P From Deuterium, M. J. Amaryan, H. Badasaryan, S. L. Careccia, G. E. Dodge, C. E. Hyde, S. E. Kuhn, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

We report a measurement of the differential cross section for the Ī³n ā†’Ļ€ā»p process from the CLAS detector at Jefferson Laboratory in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (šœƒ c.m.) between 50Ā° and 115Ā°. We confirm a previous indication of a broad enhancement around a c.m. energy (āˆš s) of 2.1 GeV at šœƒc.m. = 90Ā° in the scaled differential cross section s7 dĻƒdt and a rapid falloff in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of ā€¦

Go to article

Conformal Kernel For The Next-To-Leading-Order Bfkl Equation In š’© = 4 Super Yang-Mills Theory, Ian Balitsky, Giovanni A. Chirilli Jan 2009

Conformal Kernel For The Next-To-Leading-Order Bfkl Equation In š’© = 4 Super Yang-Mills Theory, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

Using the requirement of Mƶbius invariance of š’© = 4 super Yang-Mills amplitudes in the Regge limit, we restore the explicit form of the conformal next-to-leading-order Balitsky-Fadin-Kuraev-Lipatov (BFKL) kernel out of the eigenvalues known from the forward next-to-leading-order BFKL result.

Go to article

Measurement Of Epā†’EpĻ€įµ’ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Measurement Of Epā†’EpĻ€įµ’ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The beam spin asymmetry (BSA) in the exclusive reaction ā†’epā†’epĻ€0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The xB,Q2,t , and Ļ• dependences of the Ļ€0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sinĻ• function and their amplitudes are extracted. Overall, they are of the order of 0.04ā€“0.11 and roughly independent of t . This is the signature of a nonzero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as ā€¦

Go to article

Electroexcitation Of The Roper Resonance For 1.7 < QĀ² < 4.5gevĀ² In Ep ā†’ EnĻ€+, Clas Collaboration, M. J. Amaryan, M. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, L. M. Qin, L. B. Weinstein, J. Yun, J. Zhang Jan 2008

Electroexcitation Of The Roper Resonance For 1.7 < QĀ² < 4.5gevĀ² In Ep ā†’ EnĻ€+, Clas Collaboration, M. J. Amaryan, M. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, L. M. Qin, L. B. Weinstein, J. Yun, J. Zhang

Physics Faculty Publications

The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for 1.7 < Q2 < 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for Ļ€+ electroproduction on protons at W=1.15-1.69 GeV. The analysis is made using two approaches, dispersion relations and a unitary isobar model, which give consistent Q2 behavior of the helicity amplitudes for the gamma*p -> N (1440)P11 transition. It is found that the transverse helicity amplitude A 1/2, which is large and negative at Q2=0, becomes large and positive at Q2 similar or equal ā€¦

Go to article

Experimental Study Of Isovector Spin Sum Rules, A. Deur, P. Bosted, V. Burkert, D. Crabb, V. Dharmawardane, G. E. Dodge, T. A. Forest, K. A. Griffioen, S. E. Kuhn, R. Minehart, Y. Prok Jan 2008

Experimental Study Of Isovector Spin Sum Rules, A. Deur, P. Bosted, V. Burkert, D. Crabb, V. Dharmawardane, G. E. Dodge, T. A. Forest, K. A. Griffioen, S. E. Kuhn, R. Minehart, Y. Prok

Physics Faculty Publications

We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for 0.05< Q2 2. The integral is fit to extract the twist-4 element f pāˆ’n2 which appears to be relatively large and negative. Systematic studies of this higher twist analysis establish its legitimacy at Q2 around 1ā€‰ā€‰GeV2. We also performed an isospin decomposition of the generalized forward spin polarizability Ī³0. Although its isovector part provides a reliable test of the calculation techniques of chiral perturbation theory, our data disagree with the calculations.

Go to article

Electroproduction Of Éø(1020) Mesons At 1.4 ā‰¤ QĀ² ā‰¤ 3.8 GevĀ² Measured With The Clas Spectrometer, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde-Wright, H. G. Jungst, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, T. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Electroproduction Of Éø(1020) Mesons At 1.4 ā‰¤ QĀ² ā‰¤ 3.8 GevĀ² Measured With The Clas Spectrometer, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde-Wright, H. G. Jungst, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, T. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

Electroproduction of exclusive Ļ• vector mesons has been studied with the CLAS detector in the kinematic range 1.4 ā©½ Q2 ā©½ 3.8 GeV2 ,0.0 ā©½ tā€² ā©½3.6 GeV2 , and 2.0 ā©½ W ā©½ 3.0 GeV. The scaling exponent for the total cross section as 1/(Q2 +M2Ļ•)n was determined to be n = 2.49 Ā± 0.33. The slope of the four-momentum transfer tā€² distribution is bĻ• = 0.98 Ā± 0.17 GeV-2 . Under the assumption of s -channel helicity conservation, we determine the ratio of longitudinal to transverse cross sections ā€¦

Go to article

Measurement Of Deeply Virtual Compton Scattering Beam-Spin Asymmetries, Clas Collaboration, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Measurement Of Deeply Virtual Compton Scattering Beam-Spin Asymmetries, Clas Collaboration, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (ā†’epā†’epĪ³ ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (xB from 0.11 to 0.58, Q2 from 1 to 4.8ā€‰ā€‰GeV2, āˆ’t from 0.09 to 1.8ā€‰ā€‰GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A ā‰ƒ asinĻ•/(1+ccosĻ•). This extensive set of data can thus be used to ā€¦

Go to article

First Measurement Of Target And Double Spin Asymmetries For Ep ā†’ EpĻ€Ā° In The Nucleon Resonance Region Above The Ī” (1232), Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, G. E. Dodge, N. Guler, N. Kalantarians, A. Klein, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

First Measurement Of Target And Double Spin Asymmetries For Ep ā†’ EpĻ€Ā° In The Nucleon Resonance Region Above The Ī” (1232), Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, G. E. Dodge, N. Guler, N. Kalantarians, A. Klein, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The exclusive channel polarized proton(polarized e,e' p)Ļ€0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the Ļ€0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data ā€¦

Go to article

Cross Sections And Beam Asymmetries For E āƒ— P ā†’ EnĻ€+ In The Nucleon Resonance Region For 1.7 ā©½ Q2 ā©½ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration Jan 2008

Cross Sections And Beam Asymmetries For E āƒ— P ā†’ EnĻ€+ In The Nucleon Resonance Region For 1.7 ā©½ Q2 ā©½ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

The exclusive electroproduction process e āƒ— p ā†’ e'nĻ€+ was measured in the range of the photon virtuality Q2 =1.7-4.5 GeV2, and the invariant mass range for the n Ļ€+ system of W=1.15-1.7 GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive Ļ€+ production from protons with nearly full coverage in the azimuthal and polar angles of the nĻ€+ center-of-mass system. The nĻ€+ channel has particular sensitivity to the isospin 1/2 excited nucleon states, and together with the pĻ€0 final state will serve ā€¦

Go to article

Quark Contribution To The Small-š” Evolution Of Color Dipole, Ian Balitsky Jan 2007

Quark Contribution To The Small-š” Evolution Of Color Dipole, Ian Balitsky

Physics Faculty Publications

The small-š” deep inelastic scattering in the saturation region is governed by the nonlinear evolution of Wilson-lines operators. In the leading logarithmic approximation it is given by the Balitsky-Kovchegov (BK) equation for the evolution of color dipoles. In the next-to-leading order (NLO) the nonlinear equation gets contributions from quark and gluon loops. In this paper I calculate the quark-loop contribution to small-š” evolution of Wilson lines in the NLO. It turns out that there are no new operators at the one-loop levelā€”just as at the tree level, the high-energy scattering can be described in terms of Wilson lines. In addition, ā€¦

Go to article

Erratum: Cross Sections For The š›¾p -> K*ā° Ī£āŗ Reaction At Eš›¾ = 1.7-3.0 Gev (Physical Review C. 75, 042201), M. Amarian, H. Bagdasaryan, S. BĆ¼ltmann, G. E. Dodge, G. Gavalian, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, F. SabatiĆ©, L. B. Weinstein, Et. Al., The Clas Collaboration Jan 2007

Erratum: Cross Sections For The š›¾p -> K*ā° Ī£āŗ Reaction At Eš›¾ = 1.7-3.0 Gev (Physical Review C. 75, 042201), M. Amarian, H. Bagdasaryan, S. BĆ¼ltmann, G. E. Dodge, G. Gavalian, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, F. SabatiĆ©, L. B. Weinstein, Et. Al., The Clas Collaboration

Physics Faculty Publications

No abstract provided.

Go to article

First Measurement Of Beam-Recoil Observables CX And CZ In Hyperon Photoproduction, M. J. Amaryan, H. Bagdasaryan, H. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, R. A. Niyazov, L. M. Qin, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration Jan 2007

First Measurement Of Beam-Recoil Observables CX And CZ In Hyperon Photoproduction, M. J. Amaryan, H. Bagdasaryan, H. Bektasoglu, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, M. R. Niroula, R. A. Niyazov, L. M. Qin, F. SabatiĆ©, S. Tkachenko, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions ā†’Ī³ + p ā†’ K+ + ā†’Ī› and ā†’Ī³+p ā†’ K+ + ā†’Ī£0. The data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS) detector at the Jefferson Lab for center-of-mass energies W between 1.6 and 2.53 GeV, and for -0.85 < cos Īøc.m.K+ < +0.95. For the Ī›, the polarization transfer coefficient along the photon momentum axis, Cz, was found to be near unity for a wide range of energy and kaon production angles. The associated transverse polarization coefficient Cx is smaller than Cz by a roughly ā€¦

Go to article

Measurement Of Coherent Éø-Meson Photoproduction From The Deuteron At Low Energies, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, Et. Al., Clas Collaboration Jan 2007

Measurement Of Coherent Éø-Meson Photoproduction From The Deuteron At Low Energies, M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, Et. Al., Clas Collaboration

Physics Faculty Publications

The cross section and decay angular distributions for the coherent Éø-meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t = (pįµ§ - pÉø)2 =-2 GeV2/c2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a rescattering model. In a framework of vector meson dominance, the data are consistent with the total Éø-N cross section ĻƒÉøN at about 10 mb. If vector meson dominance is violated, a larger ĻƒÉøN is possible by introducing a ā€¦

Go to article

Cascade Production In The Reactions š›¾p ā†’ Kāŗ Kāŗ(X) And š›¾p ā†’ KāŗKāŗ Ī ā»ā»(X), M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., Clas Collaboration Jan 2007

Cascade Production In The Reactions š›¾p ā†’ Kāŗ Kāŗ(X) And š›¾p ā†’ KāŗKāŗ Ī ā»ā»(X), M. J. Amaryan, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

Photoproduction of the cascade resonances has been investigated in the reactions Ī³p ā†’ K + K +(X) and Ī³p ā†’ K + K + Ļ€ āˆ’(X). The mass splitting of the ground state (Īžāˆ’,Īž0) doublet is measured to be 5.4 Ā± 1.8 MeV/c2, consistent with existing measurements. The differential (total) cross sections for the Īžāˆ’ have been determined for photon beam energies from 2.75 to 3.85 (4.75) GeV and are consistent with a production mechanism of Yāˆ—ā†’K+Īžāˆ’ through a t-channel process. The reaction Ī³pā†’K+K+Ļ€āˆ’[Īž0] has also been investigated to ā€¦

Go to article

Cross Sections For The š›¾p -> K*ā° Ī£āŗ Reaction At Eš›¾ = 1.7-3.0 Gev, M. Amarian, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration Jan 2007

Cross Sections For The š›¾p -> K*ā° Ī£āŗ Reaction At Eš›¾ = 1.7-3.0 Gev, M. Amarian, H. Bagdasaryan, S. BĆ¼ltmann, S. L. Careccia, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

Differential cross sections for the reaction š›¾pā†’ K*0Ī£+ are presented in the photon energy range of 1.7 to 3.0 GeV. The K*0 was detected by its decay products, K+Ļ€āˆ’, in the Continuous Electron Beam Accelerator Facility's large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility. These data are the first K*0 photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor Kāˆ—-quark couplings shows good agreement with the data, except at forward angles, suggesting that ā€¦

Go to article

High-Energy Effective Action From Scattering Of Qcd Shock Waves, Ian Balitsky Jan 2006

High-Energy Effective Action From Scattering Of Qcd Shock Waves, Ian Balitsky

Physics Faculty Publications

At high energies, the relevant degrees of freedom are Wilson lines--infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops

Go to article

Differential Cross Sections For š›¾ + P ā†’ Kāŗ + Y For Ī› And Ī£ā° Hyperons, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, S. BĆ¼ltmann, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, A. V. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., Clas Collaboration Jan 2006

Differential Cross Sections For š›¾ + P ā†’ Kāŗ + Y For Ī› And Ī£ā° Hyperons, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, S. BĆ¼ltmann, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, A. V. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

High-statistics cross sections for the reactions š›¾ + p ā†’ Kāŗ + Ī› and š›¾ + p ā†’ Kāŗ + Ī£ā° have been measured using CLAS at Jefferson Lab for center-of-mass energies W between 1.6 and 2.53 GeV, and for -0.85 < cos Īø Kc.m. < +0.95. In the Kāŗ + Ī› channel we confirm a resonance-like structure near W=1.9 GeV at backward kaon angles. The position and width of this structure change with angle, indicating that more than one resonance is likely playing a role. The Kāŗ + Ī› channel at forward angles and all energies is well described by a t-channel scaling characteristic of Regge exchange, whereas the same scaling applied to the Kāŗ + Ī£ā° channel is less successful. Several existing theoretical models are compared to the data, but none provide a good representation of the results.

Go to article

First Prev Next Last