共查询到20条相似文献,搜索用时 15 毫秒
1.
Egiyan KS Asryan G Gevorgyan N Griffioen KA Laget JM Kuhn SE Adams G Amaryan MJ Ambrozewicz P Anghinolfi M Audit G Avakian H Bagdasaryan H Baillie N Ball JP Baltzell NA Barrow S Batourine V Battaglieri M Bedlinskiy I Bektasoglu M Bellis M Benmouna N Berman BL Biselli AS Blaszczyk L Bouchigny S Boiarinov S Bradford R Branford D Briscoe WJ Brooks WK Bültmann S Burkert VD Butuceanu C Calarco JR Careccia SL Carman DS Cazes A Chen S Cole PL Collins P Coltharp P Cords D Corvisiero P Crabb D Crede V 《Physical review letters》2007,98(26):262502
The reaction 2H(e,e'p)n has been studied with full kinematic coverage for photon virtuality 1.75NN transition is the primary contribution at higher momenta. 相似文献
2.
Dohrmann F Ahmidouch A Armstrong CS Arrington J Asaturyan R Avery S Bailey K Bitao H Breuer H Brown DS Carlini R Cha J Chant N Christy E Cochran A Cole L Crowder J Danagoulian S Elaasar M Ent R Fenker H Fujii Y Gan L Garrow K Geesaman DF Gueye P Hafidi K Hinton W Juengst H Keppel C Liang Y Liu JH Lung A Mack D Markowitz P Mitchell J Miyoshi T Mkrtchyan H Mtingwa SK Mueller B Niculescu G Niculescu I Potterveld D Raue BA Reimer PE Reinhold J Roche J Sarsour M Sato Y Segel RE Semenov A Stepanyan S 《Physical review letters》2004,93(24):242501
The (3,4)(Lambda)H and (4)(Lambda)H hypernuclear bound states have been observed for the first time in kaon electroproduction on (3,4)He targets. The production cross sections have been determined at Q(2)=0.35 GeV2 and W=1.91 GeV. For either hypernucleus the nuclear form factor is determined by comparing the angular distribution of the (3,4)He(e,e(')K+)(3,4)(Lambda)H processes to the elementary cross section 1H(e,e K+)Lambda on the free proton, measured during the same experiment. 相似文献
3.
Boeglin WU Coman L Ambrozewicz P Aniol K Arrington J Batigne G Bosted P Camsonne A Chang G Chen JP Choi S Deur A Epstein M Finn JM Frullani S Furget C Garibaldi F Gayou O Gilman R Hansen O Hayes D Higinbotham DW Hinton W Hyde C Ibrahim H de Jager CW Jiang X Jones MK Kaufman LJ Klein A Kox S Kramer L Kumbartzki G Laget JM LeRose J Lindgren R Margaziotis DJ Markowitz P McCormick K Meziani Z Michaels R Milbrath B Mitchell J Monaghan P Moteabbed M Moussiegt P Nasseripour R Paschke K Perdrisat C 《Physical review letters》2011,107(26):262501
The (2)H(e,e'p)n cross section at a momentum transfer of 3.5 (GeV/c)(2) was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle θ(nq) and to extract missing momentum distributions for fixed values of θ(nq) up to 0.55 GeV/c. In the region of 35°≤θ(nq)≤45° recent calculations, which predict that final-state interactions are small, agree reasonably well with the experimental data. Therefore, these experimental reduced cross sections provide direct access to the high momentum component of the deuteron momentum distribution in exclusive deuteron electrodisintegration. 相似文献
4.
Strauch S Dieterich S Aniol KA Annand JR Baker OK Bertozzi W Boswell M Brash EJ Chai Z Chen JP Christy ME Chudakov E Cochran A De Leo R Ent R Epstein MB Finn JM Fissum KG Forest TA Frullani S Garibaldi F Gasparian A Gayou O Gilad S Gilman R Glashausser C Gomez J Gorbenko V Gueye PL Hansen JO Higinbotham DW Hu B Hyde-Wright CE Ireland DG Jackson C de Jager CW Jiang X Jones C Jones MK Kellie JD Kelly JJ Keppel CE Kumbartzki G Kuss M LeRose JJ Livingston K Liyanage N Malov S Margaziotis DJ 《Physical review letters》2003,91(5):052301
We have measured the proton recoil polarization in the 4He(e-->,e(')p-->)4H reaction at Q(2)=0.5, 1.0, 1.6, and 2.6 (GeV/c)(2). The measured ratio of polarization transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a medium modification of the proton form factors predicted by a quark-meson coupling model. In addition, the measured induced polarizations agree reasonably well with the fully relativistic calculation indicating that the treatment of final-state interactions is under control. 相似文献
5.
Rvachev MM Benmokhtar F Penel-Nottaris E Aniol KA Bertozzi W Boeglin WU Butaru F Calarco JR Chai Z Chang CC Chen JP Chudakov E Cisbani E Cochran A Cornejo J Dieterich S Djawotho P Duran W Epstein MB Finn JM Fissum KG Frahi-Amroun A Frullani S Furget C Garibaldi F Gayou O Gilad S Gilman R Glashausser C Hansen JO Higinbotham DW Hotta A Hu B Iodice M Iomni R de Jager CW Jiang X Jones MK Kelly JJ Kox S Kuss M Laget JM De Leo R Lerose JJ Liatard E Lindgren R Liyanage N Lourie RW Malov S 《Physical review letters》2005,94(19):192302
We have studied the quasielastic 3He(e,e(')p)2H reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e(')p)2H cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern 3He wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models. 相似文献
6.
Vejcik S Velev G Vidal R Vilar R Vologouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C Wang CH Wang MJ Watanabe T Watts T Webb R Wenzel H Wester WC Wicklund AB Wicklund E Williams HH Wilson P Winer BL Winn D Wolbers S 《Physical review letters》2000,84(5):845-850
The transverse momentum and total cross section of e(+)e(-) pairs in the Z-boson region of 66相似文献
7.
Benmokhtar F Rvachev MM Penel-Nottaris E Aniol KA Bertozzi W Boeglin WU Butaru F Calarco JR Chai Z Chang CC Chen JP Chudakov E Cisbani E Cochran A Cornejo J Dieterich S Djawotho P Duran W Epstein MB Finn JM Fissum KG Frahi-Amroun A Frullani S Furget C Garibaldi F Gayou O Gilad S Gilman R Glashausser C Hansen JO Higinbotham DW Hotta A Hu B Iodice M Iomni R de Jager CW Jiang X Jones MK Kelly JJ Kox S Kuss M Laget JM De Leo R Lerose JJ Liatard E Lindgren R Liyanage N Lourie RW Malov S 《Physical review letters》2005,94(8):082305
Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q=1502 MeV/c and omega=840 MeV, respectively, for missing momenta p(m) up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much more extensive than that of any previous experiment. The cross section data are presented along with the effective momentum density distribution and compared to theoretical models. 相似文献
8.
V. Böhmer J. Engler W. Flauger H. Keim F. Mönnig K. Pack H. Schopper A. Babaev E. Brachmann G. Eliseev A. Ermilov Yu. Galaktionov Yu. Gorodrov Yu. Kamishkov E. Leikin V. Lubimov V. Shevchenko O. Zeldovich 《Nuclear Physics B》1975,91(2):266-278
The neutron-proton elastic differential cross section has been measured for incident momenta between 10 and 70 GeV/c and for values of the momentum transfer squared between 0.1 and 2.8 (GeV/c)2. The forward peak and the break at about ∣t∣ = 1 (GeV/c)2 are very similar to corresponding pp data. 相似文献
9.
One of the most challenging open problems in heavy quarkonium physics is the double charm production in e+e- annihilation at B factories. The measured cross section of e+e- --> J/psi + eta(c) is much larger than leading order (LO) theoretical predictions. With the nonrelativistic QCD factorization formalism, we calculate the next-to-leading order (NLO) QCD correction to this process. Taking all one loop self-energy, triangle, box, and pentagon diagrams into account, and factoring the Coulomb-singular term into the cc bound state wave function, we get an ultraviolet and infrared finite correction to the cross section of e+e- --> J/psi + eta(c) at sqrt[s] = 10:6 GeV. We find that the NLO QCD correction can substantially enhance the cross section with a K factor (the ratio of NLO to LO) of about 1.8-2.1; hence, it greatly reduces the large discrepancy between theory and experiment. 相似文献
10.
Malace SP Paolone M Strauch S Albayrak I Arrington J Berman BL Brash EJ Briscoe B Camsonne A Chen JP Christy ME Chudakov E Cisbani E Craver B Cusanno F Ent R Garibaldi F Gilman R Glamazdin O Glister J Higinbotham DW Hyde-Wright CE Ilieva Y de Jager CW Jiang X Jones MK Keppel CE Khrosinkova E Kuchina E Kumbartzki G Lee B Lindgren R Margaziotis DJ Meekins D Michaels R Park K Pentchev L Perdrisat CF Piasetzky E Punjabi VA Puckett AJ Qian X Qiang Y Ransome RD Saha A Sarty AJ Schulte E Solvignon P 《Physical review letters》2011,106(5):052501
We measured with unprecedented precision the induced polarization P(y) in (4)He(e,e'p)(3)H at Q(2)=0.8 and 1.3 (GeV/c)(2). The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are overestimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin-independent charge-exchange term in the latter calculation. 相似文献
11.
12.
Abelev BI Aggarwal MM Ahammed Z Amonett J Anderson BD Anderson M Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellingeri-Laurikainen A Bellwied R Benedosso F Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth SL Bonner BE Botje M Bouchet J Brandin AV Bravar A Burton TP Bystersky M Cadman RV Cai XZ Caines H Sánchez MC Castillo J Catu O Cebra D Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH Cheng J Cherney M 《Physical review letters》2006,97(25):252001
We report a measurement of the longitudinal double-spin asymmetry A(LL) and the differential cross section for inclusive midrapidity jet production in polarized proton collisions at square root of s = 200 GeV. The cross section data cover transverse momenta 5 < pT < 50 GeV/c and agree with next-to-leading order perturbative QCD evaluations. The A(LL) data cover 5 < pT < 17 GeV/c and disfavor at 98% C.L. maximal positive gluon polarization in the polarized nucleon. 相似文献
13.
Affolder T Akimoto H Akopian A Albrow MG Amaral P Amidei D Anikeev K Antos J Apollinari G Arisawa T Artikov A Asakawa T Ashmanskas W Azfar F Azzi-Bacchetta P Bacchetta N Bachacou H Bailey S de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Barone M Bauer G Bedeschi F Belforte S Bell WH Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Berryhill J Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K Blumenfeld B Blusk SR Bocci A Bodek A Bokhari W 《Physical review letters》2001,87(13):131802
We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A(FB), and production cross section d sigma/dM for e(+)e(-) pairs with mass M(ee)>40 GeV/c(2). The data sample consists of 108 pb(-1) of pp macro collisions at square root of s = 1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The measured asymmetry and d sigma/dM are compared with the predictions of the standard model and a model with an extra Z' gauge boson. 相似文献
14.
Gayou O Aniol KA Averett T Benmokhtar F Bertozzi W Bimbot L Brash EJ Calarco JR Cavata C Chai Z Chang CC Chang T Chen JP Chudakov E De Leo R Dieterich S Endres R Epstein MB Escoffier S Fissum KG Fonvieille H Frullani S Gao J Garibaldi F Gilad S Gilman R Glamazdin A Glashausser C Gomez J Gorbenko V Hansen JO Higinbotham DW Huber GM Iodice M de Jager CW Jiang X Jones MK Kelly JJ Khandaker M Kozlov A Kramer KM Kumbartzki G LeRose JJ Lhuillier D Lindgren RA Liyanage N Lolos GJ Margaziotis DJ 《Physical review letters》2002,88(9):092301
The ratio of the electric and magnetic form factors of the proton G(E(p))/G(M(p)), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic e(-->)p---> e(-->)p reaction. The new data presented span the range 3.5< Q(2)< 5.6 GeV(2) and are well described by a linear Q(2) fit. Also, the ratio sqrt[Q(2)] F(2(p))/F(1(p)) reaches a constant value above Q(2) = 2 GeV(2). 相似文献
15.
Balestra F Bedfer Y Bertini R Bland LC Brenschede A Brochard F Bussa MP Choi S Colantoni ML Dressler R Dzemidzic M Faivre JC Ferrero A Ferrero L Foryciarz J Fröhlich I Frolov V Garfagnini R Grasso A Heinz S Jacobs WW Kühn W Maggiora A Maggiora M Manara A Panzieri D Pfaff HW Piragino G Popov A Ritman J Salabura P Tchalyshev V Tosello F Vigdor SE Zosi G;DISTO Collaboration 《Physical review letters》2002,89(9):092001
Total and differential cross sections for the exclusive reaction pp-->pp rho observed via the pi(+)pi(-) decay channel have been measured at p(beam)=3.67 GeV/c. The observed total meson production cross section is determined to be (23.4+/-0.8+/-8) mu b and is significantly lower than typical cross sections used in model calculations for heavy-ion collisions. The differential cross sections measured indicate a strong anisotropy (approximately cos(theta(CM)(rho)) in the rho(0) meson production. 相似文献
16.
Baghdasaryan H Weinstein LB Laget JM Adhikari KP Aghasyan M Amarian M Anghinolfi M Avakian H Ball J Battaglieri M Bedlinskiy I Bennett RP Berman BL Biselli AS Bookwalter C Briscoe WJ Brooks WK Bültmann S Burkert VD Carman DS Crede V D'Angelo A Daniel A Dashyan N De Vita R De Sanctis E Deur A Dey B Dickson R Djalali C Dodge GE Doughty D Dupre R Egiyan H El Alaoui A El Fassi L Eugenio P Fegan S Gabrielyan MY Gilfoyle GP Giovanetti KL Gohn W Gothe RW Griffioen KA Guidal M Guo L Gyurjyan V 《Physical review letters》2010,105(22):222501
We have measured the 3He(e,e' pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs by using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum p(tot). For pair relative momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low p(tot) and rises to approximately 0.5 at large p(tot). This shows the dominance of tensor over central correlations at this relative momentum. 相似文献
17.
Yuan CZ Shen CP Wang P McOnie S Adachi I Aihara H Aulchenko V Aushev T Bahinipati S Balagura V Barberio E Bedny I Bitenc U Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang MC Chang P Chen A Chen KF Chen WT Cheon BG Chistov R Cho IS Choi Y Dalseno J Danilov M Dash M Eidelman S Fratina S Gabyshev N Golob B Ha H Haba J Hayasaka K Hayashii H Hazumi M Heffernan D Hokuue T Hoshi Y Hou WS Hsiung YB Hyun HJ Iijima T Ikado K Inami K Ishikawa A Itoh R Iwasaki Y Kah DH Kaji H Kang JH Katayama N 《Physical review letters》2007,99(18):182004
The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement. 相似文献
18.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Alexander J Amirikas R Aphecetche L Aronson SH Averbeck R Awes TC Azmoun R Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Berdnikov Y Bhagavatula S Boissevain JG Borel H Borenstein S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chai JS Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choi J Choudhury RK 《Physical review letters》2005,95(20):202001
19.
Alver B Back BB Baker MD Ballintijn M Barton DS Betts RR Bindel R Busza W Chai Z Chetluru V García E Gburek T Gulbrandsen K Hamblen J Harnarine I Henderson C Hofman DJ Hollis RS Hołyński R Holzman B Iordanova A Kane JL Kulinich P Kuo CM Li W Lin WT Loizides C Manly S Mignerey AC Nouicer R Olszewski A Pak R Reed C Richardson E Roland C Roland G Sagerer J Sedykh I Smith CE Stankiewicz MA Steinberg P Stephans GS Sukhanov A Szostak A Tonjes MB Trzupek A van Nieuwenhuizen GJ Vaurynovich SS Verdier R 《Physical review letters》2006,96(21):212301
We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25 < pT < 5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25 < pT < 7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2 < eta < 1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems. 相似文献
20.
Abazov VM Abbott B Abdesselam A Abolins M Abramov V Acharya BS Adams DL Adams M Ahmed SN Alexeev GD Alton A Alves GA Anderson EW Arnoud Y Avila C Babintsev VV Babukhadia L Bacon TC Baden A Baffioni S Baldin B Balm PW Banerjee S Barberis E Baringer P Barreto J Bartlett JF Bassler U Bauer D Bean A Beaudette F Begel M Belyaev A Beri SB Bernardi G Bertram I Besson A Beuselinck R Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Blazey G Blekman F Blessing S Boehnlein A Bojko NI Bolton TA 《Physical review letters》2004,92(22):221801
A search for narrow resonances that decay into tt pairs has been performed using 130 pb(-1) of data in the lepton + jets channel collected by the Dphi detector in pp collisions at square root of (s)=1.8 TeV. There is no significant deviation observed from the standard-model predictions at a top-quark mass of 175 GeV/c2. We therefore present upper limits at the 95% confidence level on the product of the production cross section and branching fraction to tt for narrow resonances as a function of the resonance mass MX. These limits are used to exclude the existence of a leptophobic top-color particle with mass MX<560 GeV/c2, using a theoretical cross section for a width GammaX=0.012MX. 相似文献