33 research outputs found

    Measurement of the Ds lifetime

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    We report precise measurement of the Ds meson lifetime. The data were taken by the SELEX experiment (E781) spectrometer using 600 GeV/c Sigma-, pi- and p beams. The measurement has been done using 918 reconstructed Ds. The lifetime of the Ds is measured to be 472.5 +- 17.2 +- 6.6 fs, using K*(892)0K+- and phi pi+- decay modes. The lifetime ratio of Ds to D0 is 1.145+-0.049.Comment: 5 pages, 2 figures submitted to Phys. Lett.

    Confirmation of the Double Charm Baryon Xi_cc+ via its Decay to p D+ K-

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    We observes a signal for the double charm baryon Xi_cc+ in the charged decay mode Xi_cc+ -> p D+ K- to complement the previously reported decay Xi_cc+ -> Lambda_c K- pi+ in data from SELEX, the charm hadro-production experiment (E781) at Fermilab. In this new decay mode we observe an excess of 5.62 events over an expected background estimated by event mixing to be 1.38+/-0.13 events. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4E-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 Gamma(Xi_cc+ -> pD+K-)/Gamma(Xi_cc+ -> Lambda_c K- pi+) = 0.36+/-0.21.Comment: 11 pages, 6 included eps figures. v2 includes improved statistical method to determine significance of observation. Submitted to PL

    Hadronic Production of Lambda_c from 600 GeV/c pion, sigma and proton beams

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    We present data from Fermilab experiment E781 (SELEX) on the hadroproduction asymmetry for anti-Lambda_c compared to Lambda_c+ as a function of xF and pt2 distributions for Lambda_c+. These data were measured in the same apparatus using incident pi-, sigma- beams at 600 GeV/c and proton beam at 540 GeV/c. The asymmetry is studied as a function of xF. In the forward hemisphere with xF >= 0.2 both baryon beams exhibit very strong preference for producing charm baryons rather than charm antibaryons, while the pion beam asymmetry is much smaller. In this energy regime the results show that beam fragments play a major role in the kinematics of Lambda_c formation, as suggested by the leading quark picture.Comment: 6 pages, 5 figures (postscript), RevTeX, submitted to Phy. Rev. Let

    First Observation of the Cabibbo-suppressed Decays Xi_c+ -> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+ and Measurement of their Branching Ratios

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    We report the first observation of two Cabibbo-suppressed decay modes, Xi_c+ -> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+. We observe 59+/-14 over a background of 87, and 22+/-8 over a background of 13 events, respectively, for the signals. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600GeV/c Sigma- beam. The branching ratios of the decays relative to the Cabibbo--favored Xi_c+ -> Xi- pi+ pi+ are measured to be B(Xi_c+ -> Sigma+ pi- pi+)/B(Xi_c+ -> Xi- pi+ pi+) = 0.48+/-0.20, and B(Xi_c+ -> Sigma- pi+ pi+)/B(Xi_c+ -> Xi- pi+ pi+) = 0.18+/-0.09, respectively. We also report branching ratios for the same decay modes of the Lambda_c+ relative to Lambda_c+ -> p K- pi+.Comment: 15 pages, 5 figures, version 2 as accepted in PL

    Total Cross Section Measurements With π- , Σ- And Protons On Nuclei And Nucleons Around 600 Gev/c

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    Total cross sections for Σ- and π- on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c . These measurements were performed with a transmission technique in the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron-nucleus cross sections and on results for σtot(Σ-N) and σtot(π-N) , which were deduced from nuclear cross sections. © 2000 Elsevier Science B.V.57901/02/15277312Langland, J.L., (1995) Ph.D. Thesis, , University of IowaKleinfelder, S.A., (1988) IEEE Trans. Nucl. Sci., 35 (1)Dersch, U., (1998) Ph.D. Thesis, HeidelbergBiagi, S.F., (1981) Nucl. Phys. B, 186, pp. 1-21Bellettini, G., (1966) Nucl. Phys., 79, pp. 609-624Schiz, A.M., (1980) Phys. Rev. D, 21, pp. 3010-3022Murthy, P.V.R., (1975) Nucl. Phys. B, 92, pp. 269-308Caso, C., (1998) Eur. Phys. J. C, 3. , http://pdg.lbl.gov/1998/contents_plots.html, and data on total cross sections from computer readable filesSchiz, A.M., (1979) Ph.D. Thesis, , Yale University(1973) Landolt Börnstein Tables, 7. , Springer editionEngler, J., (1970) Phys. Lett. B, 32, pp. 716-719Babaev, A., (1974) Phys. Lett. B, 51, pp. 501-504Glauber, R.J., (1959) Boulder Lectures, pp. 315-413Franco, V., (1972) Phys. Rev. C, 6, pp. 748-757Karmanov, V.A., Kondratyuk, L.A., (1973) JETP Lett., 18, pp. 266-268Burq, J.P., (1983) Nucl. Phys. B, 217, pp. 285-335Gross, D., (1978) Phys. Rev. Lett., 41, pp. 217-220Beznogikh, G.G., (1972) Phys. Lett. B, 39, pp. 411-413Vorobyov, A.A., (1972) Phys. Lett. B, 41, pp. 639-641Foley, K.J., (1967) Phys. Rev. Lett., 19, pp. 857-859Fajardo, L.A., (1981) Phys. Rev. D, 24, pp. 46-65Jenni, P., (1977) Nucl. Phys. B, 129, pp. 232-252Breedon, R.E., (1989) Phys. Rev. Lett. B, 216, pp. 459-465Amos, N., (1983) Phys. Rev. Lett. B, 128, pp. 343-348Amaldi, U., (1977) Phys. Rev. Lett. B, 66, pp. 390-394Amos, N., (1985) Nucl. Phys. B, 262, pp. 689-714Akopin, V.D., (1977) Sov. J. Nucl. Phys., 25, pp. 51-55Amirkhanov, I.V., (1973) Sov. J. Nucl. Phys., 17, pp. 636-637Foley, K.J., (1969) Phys. Rev., 181, pp. 1775-1793Apokin, V.D., (1976) Nucl. Phys. B, 106, pp. 413-429Burq, J.P., (1982) Phys. Lett. B, 109, pp. 124-127Dakhno, L.G., (1983) Sov. J. Nucl. Phys., 37, pp. 590-598Kazarinov, M., (1976) Sov. Phys. JETP, 43, pp. 598-606De Jager, C.W., (1974) At. Data Nucl. Data Tables, 14, pp. 479-508Donnachie, A., Landshoff, P.V., (1992) Phys. Lett. B, 296, pp. 227-232Lipkin, H., (1975) Phys. Rev. D, 11, pp. 1827-1831Barnett, R.M., (1996) Phys. Rev. D, 54, pp. 191-192Carroll, A.S., (1979) Phys. Lett. B, 80, pp. 423-427Badier, J., (1972) Phys. Lett. B, 41, pp. 387-39

    Total Cross Section Measurements with pi-, Sigma- and Protons on Nuclei and Nucleons around 600 GeV/c

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    Total cross sections for Sigma- and pi- on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c. These measurements were performed with a transmission technique adapted to the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron-nucleus cross sections and on results for sigma_tot(Sigma- N) and sigma_tot(pi- N), which were deduced from nuclear cross sections.Comment: 42 pages, submitted to Nucl.Phys.

    Nuclear Dependence Of Charm Production

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    Using 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

    Клинико-экономическое сравнение использования препаратов реслизумаб, меполизумаб и бенрализумаб в терапии тяжелой эозинофильной бронхиальной астмы

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    During last few years, the approaches to the management of patients with severe asthma have been revised. Monoclonal antibodies (MABs), inhibitors of interleukin-5 (reslizumab, mepolizumab, benralizumab) have been recently introduced for the treatment of severe eosinophilic asthma. The mentioned drugs were approved in Russia and included into the list of Vitally Essential Drugs. Aim. The aim of this study was to compare the clinical and economic consequences of the use of biological agents that antagonize IL-5 in the treatment of severe eosinophilic asthma in adults. Materials and methods. Two methods of clinical and economic research were used: assessment of the cost-effectiveness ratio and analysis of the budget impact. The effectiveness of the drugs was assessed using indirect comparison; special attention was paid to comparability of the patient groups in the studies chosen for such an assessment. Two approaches were used for calculation of the cost of therapy for severe asthma: using DRGs (applicable to most regions of Russia), and without the use of DRGs, which is relevant only for few Russian regions. results. Basing on the data obtained from a budget impact study without the use of DRG, it was shown that reslizumab was dominating for patients with body mass of up to 70 kg, while for the patients with body mass of 70 to 110 kg, mepolizumab was dominating, while utilization of reslizumab appeared to be somewhat more expensive. In the group of patients with body mass over 110 kg, mepolizumab also was dominating. The calculation of the cost-effectiveness ratio (CER) showed that reslizumab appeared to be dominating over two other MABs, The results of the study using the DRG demonstrated that the cost of an annual course of benralizumab in most cases in Russia would exceed the amount that can be compensated by Territorial Funds for Mandatory Medical Insurance to a healthcare institution for therapy of bronchial asthma in one adult patient with genetically engineered drugs. Therefore, further comparisons were made for reslizumab and mepolizumab only. Analysis of the impact on the budget demonstrated that treatment with reslizumab and mepolizumab would represent a similar burden for the budget. When applying cost-effectiveness analysis, reslizumab was more cost-effective than mepolizumab (regardless of patient body mass). conclusion. Thus, the results of the clinical and economic study suggested that, basing on the cost-effectiveness analysis, reslizumab appeared to be the dominant IL-5 antagonist (regardless of body mass if DRG approach was used and in patients with body mass up to 110 kg, if such an approach was not used). Basing on budget impact analysis, calculations without use of DRG approach showed superiority of reslizumab over mepolizumab and benralizumab for the patients with body mass up to 70 kg and the DRG-based approach showed equal burden for the budget for reslizumab and mepolizumab for the patients with any body mass. © 2020 Consilium Medikum. All rights reserved.В последние несколько лет клинико-фармакологические подходы к ведению пациентов с тяжелой бронхиальной астмой (ТА) существенно пересмотрены. Для лечения тяжелой эозинофильной астмы предложены моноклональные антитела – ингибиторы интерлейкина-5 (IL-5): реслизумаб, меполизумаб, бенрализумаб. Перечисленные препараты зарегистрированы в России и включены в список жизненно необходимых и важнейших лекарственных препаратов. Цель. Сравнение клинических и экономических последствий применения биологических препаратов, антагонистов IL-5 при терапии тяжелой эозинофильной астмы у взрослых пациентов. Материалы и методы. Использованы 2 метода клинико-экономического исследования: анализ «затраты–эффективность» и анализ влияния на бюджет. При сравнении показателей эффективности с помощью непрямого сравнения особое внимание уделено сопоставимости групп пациентов, получавших терапию сравниваемыми препаратами. При расчете стоимости терапии тяжелой бронхиальной астмы (ТА) применены два подхода: с использованием клинико-статистических групп (КСГ), что применимо к большинству регионов России, и без использования КСГ, что релевантно лишь для малого числа регионов России. Результаты. На основании проведенного исследования без использования КСГ для расчета стоимости законченного случая заболевания показано, что с точки зрения влияния на бюджет доминирующим препаратом для терапии пациентов с массой тела менее 70 кг является реслизумаб, от 70 до 110 кг – меполизумаб, и несколько более затратным является реслизумаб, в группе пациентов с массой тела более 110 кг наиболее экономичен также меполизумаб. Вычисление коэффициента «затраты–эффективность» показало, что данный коэффициент для пациентов с массой до 110 кг наименьший для реслизумаба, что свидетельствует о доминировании этого препарата у пациентов данной группы. Исследования с использованием КСГ для расчета стоимости законченного случая заболевания показали, что стоимость годового курса бенрализумаба в большинстве регионов России будет превышать сумму, которая может быть компенсирована территориальным фондом обязательного медицинского страхования на терапию бронхиальной астмы генно-инженерными препаратами у одного больного. В связи с этим дальнейшее сравнение проводилось для реслизумаба и меполизумаба. Анализ влияния на бюджет продемонстрировал равные затраты бюджета на терапию реслизумабом и меполизумабом. При этом анализ «затраты–эффективность» показал более высокую экономическую эффективность реслизумаба по сравнению с меполизумабом (независимо от массы тела пациента). Заключение. Результаты клинико-экономического исследования позволяют предположить, что на основании анализа «затраты–эффективность» доминирующим препаратом-антагонистом IL-5 является реслизумаб [для всех пациентов с тяжелой эозинофильной астмой (независимо от массы тела) при использовании КСГ и пациентов с массой тела до 110 кг без использования КСГ]. Анализ влияния на бюджет демонстрирует наиболее высокую экономичность реслизумаба для пациентов с массой тела до 70 кг (без применения КСГ), при использовании КСГ затраты бюджета для меполизумаба и реслизумаба равны у пациентов с любой массой тела
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