58 research outputs found
Study of the lineshape of the chi(c1) (3872) state
A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations
Measurement of the CKM angle in and decays with
A measurement of -violating observables is performed using the decays
and , where the meson is
reconstructed in one of the self-conjugate three-body final states and (commonly denoted ). The decays are analysed in bins of the -decay phase space, leading
to a measurement that is independent of the modelling of the -decay
amplitude. The observables are interpreted in terms of the CKM angle .
Using a data sample corresponding to an integrated luminosity of
collected in proton-proton collisions at centre-of-mass
energies of , , and with the LHCb experiment,
is measured to be . The hadronic
parameters , , , and ,
which are the ratios and strong-phase differences of the suppressed and
favoured decays, are also reported
Measurement of CP asymmetries and branching fraction ratios of B− decays to two charm mesons
The asymmetries of seven decays to two charm mesons are measured using data corresponding to an integrated luminosity of of proton-proton collisions collected by the LHCb experiment. Decays involving a or meson are analysed by reconstructing only the or decay products. This paper presents the first measurement of and , and the most precise measurement of the other five asymmetries. There is no evidence of violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured.The CP asymmetries of seven B decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9 fb of proton-proton collisions collected by the LHCb experiment. Decays involving a D or meson are analysed by reconstructing only the D or decay products. This paper presents the first measurement of (B→D) and (B→D), and the most precise measurement of the other five CP asymmetries. There is no evidence of CP violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured.[graphic not available: see fulltext]The asymmetries of seven decays to two charm mesons are measured using data corresponding to an integrated luminosity of of proton-proton collisions collected by the LHCb experiment. Decays involving a or meson are analysed by reconstructing only the or decay products. This paper presents the first measurement of and , and the most precise measurement of the other five asymmetries. There is no evidence of violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured
Study of the doubly charmed tetraquark T+cc
Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
Search For Poliovirus Carriers Among People With Primary Immune Deficiency Diseases In The United States, Mexico, Brazil, And The United Kingdom
Objective: To estimate the rate of long-term poliovirus excretors in people known to have B-cell immune deficiency disorders. Methods: An active search for chronic excretors was conducted among 306 persons known to have immunoglobulin G (IgG) deficiency in the United States, Mexico, Brazil, and the United Kingdom, and 40 people with IgA deficiency in the United States. Written informed consent or assent was obtained from the participants or their legal guardians, and the studies were formally approved. Stool samples were collected from participants and cultured for polioviruses. Calculation of the confidence interval for the proportion of participants with persistent poliovirus excretion was based on the binomial distribution. Findings: No individuals with long-term excretion of polioviruses were identified. Most participants had received oral poliovirus vaccine (OPV) and almost all had been exposed to household contacts who had received OPV. Polioviruses of recent vaccine origin were transiently found in four individuals in Mexico and Brazil, where OPV is recommended for all children. Conclusion: Although chronic poliovirus excretion can occur in immunodeficient persons, it appears to be rare.82138Benyesh-Melnick, M., Melnick, J.L., Rawls, W.E., Wimberly, I., Oro, J.B., Ben-Porath, E., Studies of the immunogenicity, communicability and genetic stability of oral poliovaccine administered during the winter (1967) American Journal of Epidemiology, 86, pp. 112-136Melnick, J.L., Benyesh-Melnick, M., Brennan, J.C., Studies on live poliovirus vaccines. Its neurotropic activity in monkeys and its increased neurovirulence after multiplication in vaccinated children (1959) JAMA, 171, pp. 1165-1172Gelfand, H.M., Potash, L., LeBlanc, D.R., Fox, J.P., Revised preliminary report on the Louisiana observations of the natural spread within families of living vaccine strains of poliovirus (1959) Live Poliovirus Vaccines: Papers Presented and Discussions Held at the First International Conference on Live Poliovirus Vaccines, , Special Publication No. 44. Washington (DC): Pan American Sanitary BureauFox, J.P., Gelfand, H.M., LeBlanc, D.R., Potash, L., Clemmer, D.I., LaPenta, D., The spread of vaccine strains of poliovirus in the household and in the community in southern Louisiana (1961) International Poliomyelitis Congress, Ed. Poliomyelitis: Papers and Discussions Presented at the Fifth International Poliomyelitis Conference, pp. 368-383. , Philadelphia: LippincottSutter, R.W., Cochi, S.L., Melnick, J.L., Live attenuated poliovirus vaccines (1999) Vaccines, 3rd Ed., pp. 364-408. , Plotkin SA, Orenstein WA, editors. Philadelphia: WB SaundersModlin, J.F., Coxsackieviruses, echoviruses, and newer enteroviruses (2000) Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 5th Ed., pp. 1904-1919. , Mandell GL, Bennett JE, Dolin R, editors. Philadelphia (PA): Churchill-LivingstoneWood, D.J., Sutter, R.W., Dowdle, W.R., Stopping poliovirus vaccination after eradication: Issues and challenges (2000) Bulletin of the World Health Organization, 78, pp. 347-357Kew, O.M., Sutter, R.W., Nottay, B.K., McDonough, M.J., Prevots, D.R., Quick, L., Prolonged replication of a type 1 vaccine-derived poliovirus in an immunodeficient patient (1998) Journal of Clinical Microbiology, 36, pp. 2893-2899Buttinelli, G., Donati, V., Fiore, S., Marturano, J., Plebani, A., Balestri, P., Nucleotide variation in Sabin type 2 poliovirus from an immunodeficient patient with poliomyelitis (2003) Journal of General Virology, 84, pp. 1215-1221John, T.J., Walker, D.H., Enterovirus infections, including poliomyelitis (1999) Tropical Infectious Diseases, Principles, Pathogens, and Practice, pp. 1123-1132. , Guerrant RL, Walker DH, Weller PF, editors. Philadelphia: Churchill LivingstoneMinor, P., Characteristics of poliovirus strains from long-term excretors with primary immunodeficiencies (2001) Developmental Biology, 105, pp. 75-80Minor, P.D., Ferguson, J.A., Icenogle, J.P., Antigenic and molecular evolution of the vaccine strain of type 3 poliovirus during the period of excretion by a primary vaccinee (1986) Journal of General Virology, 67, pp. 693-706Dunn, G., Begg, N.T., Cammack, N., Minor, P.D., Virus excretion and mutation by infants following primary vaccination with live oral poliovaccine from two sources (1990) Journal of Medical Virology, 32, pp. 92-95Sutter, R.W., Tangermann, R.H., Aylward, R.B., Cochi, S.L., Poliomyelitis eradication: Progress, challenges for the end game, and preparation for the post-eradication era (2001) Infectious Disease Clinics of North America, 15, pp. 41-64Conley, M.E., Notarangelo, L.D., Etzioni, A., Diagnostic criteria for primary immunodeficiencies. Representing PAGID (Pan-American Group for Immunodeficiency) and eSID (European Society for Immunodeficiencies) (1999) Clinical Immunology, 93, pp. 190-197(1997) Manual of the Virological Investigation of Poliomyelitis, , Geneva: World Health Organization. WHO document WHO/EPI/GEN/9701Liu, H.M., Zheng, D.P., Zhang, L.B., Oberste, M.S., Pallansch, M.A., Kew, O.M., Molecular evolution of a type 1 wild-vaccine poliovirus recombinant during widespread circulation in China (2000) Journal of Virology, 74, pp. 11153-11161Savilahti, E., Klemola, T., Carlsson, B., Mellander, L., Stenvik, M., Hovi, T., Inadequacy of mucosal IgM antibodies in selective IgA deficiency excretion of attenuated polio viruses is prolonged (1988) Journal of Clinical Immunology, 8, pp. 89-94Triki, H., Barbouche, M.R., Bahri, O., Bejaoui, M., Dellagi, K., Community-acquired poliovirus infection in children with primary immunodeficiency in Tunisia (2003) Journal of Clinical Microbiology, 41, pp. 1203-1211Hammon, W.D., Coriell, L.L., Wehrle, P.F., Stokes, J., Evaluation of Red Cross gammaglobulin as a prophylactic agent for poliomyelitis. 4. Final report of results based on clinical diagnosis (1953) JAMA, 151, pp. 1272-1285Halliday, E., Winkelstein, J., Webster, A.D., Enteroviral infections in primary immunodeficiency (PID): A survey of morbidity and mortality (2003) The Journal of Infection, 46, pp. 1-8Buttinelli, G., Donati, V., Fiore, S., Marturano, J., Plebani, A., Balestri, P., Nucleotide variation in Sabin type 2 poliovirus from an immunodeficient patient with poliomyelitis (2003) Journal of General Virology, 84, pp. 1215-1221Cunningham-Rundles, C., Bodian, C., Common variable immunodeficiency: Clinical and immunological features of 248 patients (1999) Clinical Immunology, 92, pp. 34-48Kew, O., Morris-Glasgow, V., Landaverde, M., Burns, C., Shaw, J., Garib, Z., Outbreak of poliomyelitis in Hispaniola associated with circulating type 1 vaccine-derived poliovirus (2002) Science, 296, pp. 356-359Halsey, N.A., Commentary: Poliomyelitis and unnecessary injections (2003) International Journal of Epidemiology, 32, pp. 278-279Halsey, N.A., Combination vaccines: Defining and addressing current safety concerns (2001) Clinical Infectious Diseases, 33 (SUPPL. 4), pp. S312-S31
Observation of structure in the J/ψ-pair mass spectrum
Using proton-proton collision data at centre-of-mass energies of √s = 8 and 13 TeV recorded by the
LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9 fb1
, the
invariant mass spectrum of J/ψ pairs is studied. A narrow structure around 6.9 GeV=c2 matching the lineshape of a resonance and a broad structure just above twice the J/ψ mass are observed. The deviation of
the data from nonresonant J/ψ-pair production is above five standard deviations in the mass region
between 6:2 and 7:4 GeV=c2, covering predicted masses of states composed of four charm quarks. The
mass and natural width of the narrow X6900 structure are measured assuming a Breit-Wigner
lineshape
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