55 research outputs found
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The lead-glass electromagnetic calorimeter for the SELEX experiment
No full textA large-acceptance, highly segmented electromagnetic lead glass calorimeter for Experiment E781 (SELEX) at Fermi National Acceleration Laboratory was designed and built. This detector has been used to reconstruct photons and electrons with energies ranging from few GeV up to 500 GeV in the collisions of the 650 GeV {Sigma}{sup -} hyperons and {pi}{sup -} mesons with the target nucleons. The design, calibration and performance of the calorimeter are described. Energy resolution and position resolution are assessed using both calibration electron beams and {pi}{sup 0} mesons reconstructed in 650 GeV hadron-hadron interactions. The performance of the calorimeter in selecting resonant states that involve photons is demonstrated
Nuclear Dependence Of Charm Production
No full textUsing data taken by SELEX during the 1996-1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with ∑ -, p, π -, and π + beams. Parametrizing the dependence of the inclusive production cross section on the atomic number A as A α, we determine α for D +, D 0, D s +, D +(2010), Λ c +, and their respective anti-particles, as a function of their transverse momentum p t and scaled longitudinal momentum x F . Within our statistics there is no dependence of α on x F for any charm species for the interval 0.1<x F <1.0. The average value of α for charm production by pion beams is α meson=0.850±0.028. This is somewhat larger than the corresponding average α baryon=0.755±0.016 for charm production by baryon beams (∑ -, p). © 2009 Springer-Verlag/Società Italiana di Fisica.644637644Cobbaert, H., (1987) Phys. Lett. B, 191, p. 456. , 10.1016/0370-2693(87)90639-3 1987PhLB.191.456CCobbaert, H., (1988) Phys. Lett. B, 206, p. 546. , 10.1016/0370-2693(88)91627-9Cobbaert, H., (1988) Phys. Lett. B, 213, p. 395. , 10.1016/0370-2693(88)91783-2 1988PhLB.213.395CLeitch, M.J., (2000) Phys. Rev. Lett., 84, p. 3256. , 10.1103/PhysRevLett.84.3256 2000PhRvL.84.3256L arXiv:nucl-ex/9909007Alessandro, B., Alexa, C., Arnaldi, R., Atayan, M., Baglin, C., Baldit, A., Beole, S., Willis, N., Charmonium production and nuclear absorption in p-A interactions at 450 GeV (2004) European Physical Journal C, 33 (1), pp. 31-40. , DOI 10.1140/epjc/s2003-01539-yAbt, I., (2009) Eur. Phys. J. C, 60, p. 525. , 10.1140/epjc/s10052-009-0965-7 2009EPJC.60.525A arXiv:0812.0734 [hep-ex]Heller, K.J., (1977) Phys. Rev. D, 16, p. 2737. , 10.1103/PhysRevD.16.2737 1977PhRvD.16.2737HSkubic, P., (1978) Phys. Rev. D, 18, p. 3115. , 10.1103/PhysRevD.18.3115 1978PhRvD.18.3115SAleev, A.N., (1987) Sov. J. Nucl. Phys., 46, p. 657. , [Yad. Fiz. 46, 1127 (1987)]Vecko, M., (1989) Czech. J. Phys. B, 39, p. 297. , 10.1007/BF01597781 1989CzJPh.39.297VAdamovich, M., (1992) Phys. Lett. B, 284, p. 453. , 10.1016/0370-2693(92)90460-L 1992PhLB.284.453AAlves, G.A., (1993) Phys. Rev. Lett., 70, p. 722. , 10.1103/PhysRevLett.70.722 1993PhRvL.70.722AAlves, G.A., (1994) Phys. Rev. D, 49, p. 4317. , 10.1103/PhysRevD.49.R4317 1994PhRvD.49.4317ALeitch, M.J., (1994) Phys. Rev. Lett., 72, p. 2542. , 10.1103/PhysRevLett.72.2542 1994PhRvL.72.2542LAdamovich, M., (1997) Nucl. Phys. B, 495, p. 3. , 10.1016/S0550-3213(97)00223-X 1997NuPhB.495.3AApanasevich, L., (1997) Phys. Rev. D, 56, p. 1391. , 10.1103/PhysRevD.56.1391 1997PhRvD.56.1391A arXiv:hep-ex/9702014Abt, I., (2007) Eur. Phys. J. C, 52, p. 531. , 10.1140/epjc/s10052-007-0427-z 2007EPJC.52.531A arXiv:0708.1443 [hep-ex]Duffy, M.E., (1985) Phys. Rev. Lett., 55, p. 1816. , 10.1103/PhysRevLett.55.1816 1985PhRvL.55.1816DVogt, R., The A dependence of open charm and bottom production (2003) International Journal of Modern Physics E, 12 (2), pp. 211-269. , DOI 10.1142/S0218301303001272Lourenco, C., Wohri, H.K., Heavy-flavour hadro-production from fixed-target to collider energies (2006) Physics Reports, 433 (3), pp. 127-180. , DOI 10.1016/j.physrep.2006.05.005, PII S0370157306001815Frawley, A.D., Ullrich, T., Vogt, R., (2008) Phys. Rept., 462, p. 125. , 10.1016/j.physrep.2008.04.002 2008PhR.462.125F arXiv:0806.1013 [nucl-ex]Russ, J.S., (1998) Proceedings of the 29th International Conference on High Energy Physics II World Scientific Singapore, 1259. , A. Astbury (eds), et al. arXiv:hep-ex/9812031Russ, J.S., (1998) Proceedings of the 29th International Conference on High Energy Physics, 2, p. 1259. , ed. by A. Astbury, et al. (World Scientific, Singapore) arXiv:hep-ex/9812031Engelfried, J., (1999) Nucl. Instrum. Methods A, 431, p. 53. , 10.1016/S0168-9002(99)00043-1 1999NIMPA.431.53E arXiv:hep-ex/9811001Kushnirenko, A., Alkhazov, G., Atamantchouk, A.G., Balatz, M.Y., Bondar, N.F., Cooper, P.S., Dauwe, L.J., Vishnyakov, V.E., Precision measurements of the ∧c+ and D 0 lifetimes (2001) Physical Review Letters, 86 (23), pp. 5243-5246. , DOI 10.1103/PhysRevLett.86.5243Garcia, F.G., (2002) Phys. Lett. B, 528, p. 49. , 10.1016/S0370-2693(01)01484-8 2002PhLB.528.49S arXiv:hep-ex/0109017Kaya, M., (2003) Phys. Lett. B, 558, p. 34. , 10.1016/S0370-2693(03)00246-6 2003PhLB.558.34S arXiv:hep-ex/0302039Brodsky, S.J., Kopeliovich, B., Schmidt, I., Soffer, J., (2006) Phys. Rev. D, 73, p. 113005. , 2006PhRvD.73k3005B arXiv:hep-ph/0603238Adamovich, M.I., (2003) Eur. Phys. J. C, 26, p. 357. , 10.1140/epjc/s2002-01073-6 2003EPJC.26.357WA. Blanco-Covarrubias, et al. (SELEX Collaboration), in preparatio
Confirmation of the doubly charmed baryon Epsilon(+)(cc)(3520) via its decay to pD(+)K(-)
No full textWe observe a signal for the doubly charmed baryon Xi(cc)(+) in the decay mode Xi(cc)(+) -> pD(+)K(-) to complement the previous cc reported decay Xi(cc)(+) -> Lambda(c)(+)K(-)pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38 +/- 0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8 sigma. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4 x 10(-4). The observed mass of this state is 3518 +/- 3 MeV/c(2), consistent with the published result. Averaging the two results gives a mass of 3518.7 +/- 1.7 MeV/c(2). The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36 +/- 0.21. (c) 2005 Elsevier B.V. All rights reserved
First Observation of a narrow Charm-Strange Meson D+(SJ)(2632)-->D+(S) eta and D0 K+
No full textWe report the first observation of a charm-strange meson D-sJ(+)(2632) at a mass of 2632.5+/-1.7 MeV/c(2) in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, D(s)(+)eta and (DK+)-K-0. In the D(s)(+)eta decay mode we observe a peak with 101 events over a combinatoric background of 54.9 events at a mass of 2635.4+/-3.3 MeV/c(2). There is a corresponding peak of 21 events over a background of 6.9 at 2631.5+/-2.0 MeV/c(2) in the decay mode (DK+)-K-0. The decay width of this state is <17 MeV/c(2) at 90% confidence level. The relative branching ratio Gamma((DK+)-K-0)/Gamma(D(s)(+)eta) is 0.14+/-0.06. The mechanism that keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the D(s)(+)eta decay mode
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Measurement of the Omega0(c) lifetime
No full textThe authors report a precise measurement of the {Omega}{sub c}{sup 0} lifetime. The data were taken by the SELEX (E781) experiment using 600 GeV/c {Sigma}{sup -}, {pi}{sup -} and p beams. The measurement has been made using 83 {+-} 19 reconstructed {Omega}{sub c}{sup 0} in the {Omega}{sup -} {pi}{sup -}{pi}{sup +}{pi}{sup +} and {Omega}{sup -} {pi}{sup +} decay modes. The lifetime of the {Omega}{sub c}{sup 0} is measured to be 65 {+-} 13(stat) {+-} 9(sys) fs
Upper limit on the decay Sigma(1385)(-) -> Sigma(-)gamma and cross section for gamma Sigma(-) -> Lambda pi(-)
No full textPolarization of Σ+ hyperons produced by 800 GeV/c protons on Cu and Be
No full textWe show that Σ+ hyperons produced by 800 GeV/c protons on targets of Be and Cu have significant polarizations (15-20%). These polarizations persist at values of pt = 2 GeV/c and a wide range of xF. The polarizations from the Cu target are consistently less than from Be. The average ratio of the Σ+ polarization from Cu to that from Be is 0.68 ± 0.08.Ball State University, Muncie, IN 47306Bogazici Univerity, Bebek 34342 IstanbulCarnegie-Mellon University, Pittsburgh, PA 15213Centro Brasileiro de Pesquisas Físicas, Rio de JaneiroFermi National Acceleratory Laboratory, Batavia, IL 60510Institute for High Energy Physics, ProtvinoInstitute for High Energy Physics, BeijingInstitute of Theoretical and Experimental Physics, MoscowMax-Planck-Institut für Kernphysik 69117, HeidelbergMoscow State University, MoscowPetersburg Nuclear Physics Institute, St. PetersburgTel Aviv University, 69978 Ramat AvivUniversidad Autónoma de San Luis Potosí, San Luis PotosíUniversidade Ferderal da Paraíba, ParaíbaUniversity of Bristol, Bristol BS8 1TLUniversity of Iowa, Iowa City, IA 52242University of Michigan-Flint, Flint, MI 48502University of Rome 'La Sapienza' INFN, RomeUniversity of Sao Paulo, Sao PauloUniversity of Trieste INFN, TriesteLegal Department Oracle Corporation, Redwood Shores, CAInfinion, MünchenImperial College, London SW7 2BZInstituto de Física Universidade Estadual de Campinas UNICAMP, Sao PauloPhysik-Department Technische Universität München, 85748 GarchingThe Boston Consulting Group, MünchenInstituto de Física Teórica Universidade Estadual Paulista, Sao PauloLucent Technologies, Naperville, ILSPSS Inc, Chicago, ILDOE, Germantown, MDSiemens Medizintechnik, ElangenDeutsche Bank AG, EschbornInstituto de Física Teórica Universidade Estadual Paulista, Sao Paul
First Observation Of The Doubly Charmed Baryon Ξcc+
No full textThe first experimental evidence for one of the six predicted baryon states which contain two valence charmed quarks-the doubly charmed baryons. As such, there were many predictions of the masses and other properties of these states. The properties of doubly charmed baryons provide a new window into the structure of baryonic matter.8911112001/1112001/5Groom, D.E., (2000) Eur. Phys. J. C, 15, p. 1. , Particle Data GroupDerujula, A., Georgi, H., Glashow, S., (1975) Phys. Rev. D, 12, p. 147Savage, M., Wise, M., (1990) Phys. Lett. B, 248, p. 177Körner, J.G., Krämer, M., Pirjol, D., (1994) Prog. Part. Nucl. Phys., 33, p. 787hep-ph/0201071, see Refs. [111-124]Mattson, M., (2002), Ph.D. thesis, Carnegie Mellon UniversityRuss, J.S., (1998) Proceedings of the 29th International Conference on High Energy Physics, 1998, 2, p. 1259. , SELEX Collaborationedited by A. Astbury (World Scientific, Singapore,)hep-ex/9812031Engelfried, J., (1999) Nucl. Instrum. Methods Phys. Res., Sect. A, 431, p. 53Kushnirenko, A., (2001) Phys. Rev. Lett., 86, p. 5243Garcia, F., (2002) Phys. Lett. B, 528, p. 49noteMoinester, M., (1996) Z. Phys. A, 355, p. 349Kiselev, V., Likhoded, A., (2001), hep-ph/0103169and references thereinBjorken, J.B., (1985), Report No. Fermilab-Conf-85/69Aoki, S., (1987) Phys. Lett. B, 187, p. 185Barlag, S., (1991) Phys. Lett. B, 257, p. 519. , ACCMOR CollaborationRatti, S., Proceedings of the 5th International Conference on Hyperons, Charm and Beauty Hadrons, Vancouver, B.C., 2002, , www.hep.vanderbilt.edu/-stenson/xicc/xicc_focus.html, (to be published)Abe, K., Belle Collaborationhep-ex/020510
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Polarization of Lambda0 and anti-Lambda0 inclusively produced by 610-GeV/c Sigma- and 525-GeV/c proton beams
No full textWe have measured the polarization of {Lambda}{sup 0} and {bar {Lambda}{sup 0}} inclusively produced by 610 GeV/c {Sigma}{sup -} and 525 GeV/c proton beams in the experiment SELEX during the 1996/7 fixed target run at Fermilab. The polarization was measured as a function of the {Lambda} longitudinal momentum fraction x{sub F} and transverse momentum p{sub t}. For the {Lambda}{sup 0} produced by {Sigma}{sup -} the polarization is increasing with x{sub F} , from slightly negative at x{sub F} {approx} 0 to about 15% at large x{sub F} ; it shows a non-monotonic behavior as a function of p{sub t}. For the proton beam, the {Lambda}{sup 0} polarization is negative and decreasing as a function of x{sub F} and p{sub t}. The {bar {Lambda}{sup 0}} polarization is compatible with 0 for both beam particles over the full kinematic range. The target dependence was examined but no statistically significant difference was found
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Nuclear Dependence of Charm Production
No full textWith data taken by SELEX, which accumulated data during the 1996-1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with {Sigma}{sup -}, p, {pi}{sup -}, and {pi}{sup +} beams. Parameterizing the production cross section {infinity} A{sup {alpha}}, A being the atomic number, we determine {alpha} for D{sup +}, D{sup 0}, D{sub s}{sup +}, D{sup +}(2010), {Lambda}{sub c}{sup +}, and their respective anti-particles, as a function of their transverse momentum p{sub t} and scaled longitudinal momentum x{sub F}. Within our statistics there is no dependence of {alpha} on x{sub F} for any charm species for the interval 0.1 < x{sub F} < 1.0. The average value of {alpha} for charm production by pion beams is {alpha}{sub meson} = 0.850 {+-} 0.028. This is somewhat larger than the corresponding average {alpha}{sub baryon} = 0.755 {+-} 0.016 for charm production by baryon beams ({Sigma}{sup -}, p)
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