Measurement of the Λb0 decay form factor

Abdallah, J.; Abreu, P.; Adam, W.; Adžić, P.; Albrecht, Thomas; Alderweireld, T.; Alemany–Fernández, R.; Allmendinger, T.; Allport, P. P.; Amaldi, U.; Amapane, N.; Amato, S.; Arnoud, Y.; Ask, S.; Åsman, B.; Augustin, J. E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D. Y.; Barker, G. J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K. H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A. C.; Bérat, C.; Berggren, M.; Berntzon, L.; Bertrand, Daniel; Besançon, M.; Besson, N.; Blöch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T. J. V.; Boyko, I. R.; Bračko, M.; Brenner, R.; Brodet, E.; Brückman, P.; Brunet, J. M.; Bugge, L.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N. F.; Cavallo, F. R.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S. U.; Cieślik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M. J.; Crawley, Brian; Crennell, D.; Cuevas, J.; D’Hondt, J.; Dalmau, J.; Silva, T. Da; Silva, W. Da; Ricca, G. Della; Angelis, A. De; Boer, W. De; Clercq, C. De; Lotto, B. De; Maria, N. De; Min, A. De; Paula, L. De; Ciaccio, L. Di; Simone, A. Di; Doroba, K.; Drees, J.; Dris, M.; Eigen, G.; Ekelöf, T.; Ellert, M.; Elsing, M.; Santo, M. C. Espírito; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernández, J. P.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; García, C.; Gavillet, Ph.; Gazis, E. N.; Gokieli, R.; Glob, B.; Gómez-Ceballos, G.; Gonçalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S. O.; Holt, P. J.; Houlden, M.; Hultqvist, K.; Jackson, J. N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, Erik; Johansson, P.; Jönsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kerševan, B. P.; Kerzel, U.; Kiiskinen, A.; King, B. T.; Kjaer, N. J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lämsä, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J. H.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Maréchal, B.; Margoni, M.; Marin, J. C.; Mariotti, C.; Μάρκου, Α.; Martínez-Rivero, C.; Mašík, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; McNulty, R.; Meroni, C.; Meyer, W. T.; Miagkov, A.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Mönig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S. Carrillo; Morettini, P.; Muêller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W. J.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F. L.; Nawrocki, K.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mlucha, A.; Obraztsov, V.; Olshevski, A. G.; Onofre, A.; Orava, R.; Österberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.; Pałka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M. E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rameš, J.; Ramler, L.; Read, A. L.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Řídký, J.; Rivero, M.; Rodríguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E. I.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A. M.; Sekulin, R.; Siebel, M.; Sisakian, A. N.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M. M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.; Tegengeldt, F.; Timmermans, J.; Tkatchev, L. G.; Tobin, M.; Todorovova, S.; Tomé, B.; Tonazzo, A.; Tortosa, P.; Trávničék, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M. L.; Tyapkin, I. A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Dam, P. Van; Eldik, J. Van; Lysebetten, A. Van; Remortel, N. Van; Vulpen, I. van; Vegni, G.; Veloso, F.; Vénus, W.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimin, N. I.; Zintchenko, A.; Župan, M.; Antilogus, P.

doi:10.1016/j.physletb.2004.01.086

Cited by 35 publications

(24 citation statements)

References 37 publications

Supporting

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“…A similar though not identical result is obtained by the DELPHI Collaboration [5]. The corresponding differential decay rate is shown in Fig.…”

Section: Form Factors Insupporting

confidence: 84%

Prospects for improvedΛcbranching fractions

Rosner

2012

Phys. Rev. D

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The experimental uncertainty on the branching fraction B(Λ c → pK − π + ) = (5.0 ± 1.3)% has not decreased since 1998, despite a much larger data sample. Uncertainty in this quantity dominates that in many other quantities, including branching fractions of Λ c to other modes, branching fractions of b-flavored baryons, and fragmentation fractions of charmed and bottom quarks. Here we advocate a lattice QCD calculation of the form factors in Λ c → Λℓ + ν ℓ (the case ℓ = e + is simpler as the mass of the lepton can be neglected). Such a calculation would yield an absolute prediction for the rate for Λ c → Λℓ + ν ℓ . When combined with the Λ c lifetime, it could provide a calibration for an improved set of Λ c branching fractions as long as the accuracy exceeds about 25%.PACS numbers: 14.20.Lq, 14.65.Dw, 13.30.Ce, 12.38.Gc I INTRODUCTIONDespite the accumulation of a vastly greater sample of charmed particles in e + e − , ep, and hadron-hadron collisions, the most accurately known branching fraction for the decay of the lowest-lying charmed baryon Λ c , B(Λ c → pK − π + ) = (5.0 ± 1.3)%, has remained at the same value since 1998. It was only pinned down to that accuracy thanks to constructive suggestions by Dunietz [1]. This branching fraction sets the scale for a number of other quantities which depend on it. Many other Λ c branching fractions are measured through their ratio to the pK − π + mode [2]. It sets the scale for b-flavored baryon branching fractions, and governs fragmentation fractions of charm and bottom quarks into baryons.In the present paper we advocate improvement of accuracy of the semileptonic branching fraction B(Λ c → Λe + ν e ), whose current value is (2.1 ± 0.6)%, via a lattice QCD calculation of the relevant form factors. Such calculations have been performed for the semileptonic decays of charmed mesons, D → Kℓν ℓ and D → πℓν ℓ [3], which are characterized by two form factors. Although four form factors are relevant to Λ c → Λℓν ℓ in the limit of zero lepton mass, the difficulty of such a calculation is outweighed by its importance. A calculation enabling the prediction of the rate for Λ c → Λe + ν e (and hence its branching fraction, given τ (Λ c ) = 200 ± 6 fs [2]) to an accuracy of better than about 25% would represent an improvement on a wide variety of key quantities.In Section II we review various quantities which could profit from improvement in the accuracy of B(Λ c → Λe + ν e ). We discuss in Section III the present status of understanding of form factors in this decay. The corresponding semileptonic decay Λ b → Λ c e −ν e , to which the Heavy Quark Effective Theory (HQET) can be applied, is treated in Section IV. Some remarks are made in Section V regarding the "calibrating" mode Λ c → pK − π + , while Section V concludes.

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“…A similar though not identical result is obtained by the DELPHI Collaboration [5]. The corresponding differential decay rate is shown in Fig.…”

Section: Form Factors Insupporting

confidence: 84%

Prospects for improvedΛcbranching fractions

Rosner

2012

Phys. Rev. D

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show abstract

“…+0.72 −1.00 (syst) [2]. Within the large error bars the experimental slope value is compatible with the HQET sum rule results of [3,4] although the experimental central values of [2] are considerably higher than the theoretical sum rule results.…”

supporting

confidence: 78%

“…In the baryon sector a particular example is the semileptonic decay Λ b → Λ c ℓν ℓ . In view of the fact that a recent experiment from DELPHI [2] shows a discrepancy with the results of previous QCD sum rule calculations [3,4] an updated sum rule analysis for the baryonic Λ b → Λ c form factor is called for.…”

mentioning

confidence: 99%

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Note on the slope parameter of the baryonic Λb→Λc Isgur–Wise function

et al. 2005

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Using the framework of the Heavy Quark Effective Theory we have re-analyzed the Isgur-Wise function describing semileptonic Λ b → Λ c decays in the QCD sum rule approach. The slope parameter of the Isgur-Wise function is found to be ρ 2 = 1.35 ± 0.12, which is consistent with an experimental measurement and a lattice calculation. To O(1/m b , 1/m c ) of the heavy quark expansion the integrated Λ b decay width is used to extract the CKM matrix element V cb for which we obtain a value of |V cb | = 0.041±0.004 in excellent agreement with the value of |V cb | determined from semileptonic B → D * decays.

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“…The hadronic matrix elements for the semileptonic decay Λ Q → Λ Q ′ are parameterized in terms of six invariant form factors: (23) where u Λ Q (v, s) and u Λ Q ′ (v ′ , s ′ ) are Dirac spinors of the initial and final baryon with fourvelocities v and v ′ , respectively; q = M Λ Q ′ v ′ − M Λ Q v, and…”

Section: A Heavy Baryons With the Scalar Diquarkmentioning

confidence: 99%

Semileptonic decays of heavy baryons in the relativistic quark model

2006

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Semileptonic decays of heavy baryons consisting of one heavy (Q = b, c) and two light (q = u, d, s) quarks are considered in the heavy-quark-light-diquark approximation. The relativistic quasipotential equation is used for obtaining masses and wave functions of both diquarks and baryons within the constituent quark model. The weak transition matrix elements are expressed through the overlap integrals of the baryon wave functions. The Isgur-Wise functions are determined in the whole accessible kinematic range. The exclusive semileptonic decay rates and different asymmetries are calculated with applying the heavy quark 1/m Q expansion. The evaluated Λ b → Λ c lν decay rate agrees with its experimental value.

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Measurement of the Λb0 decay form factor

Abstract: The form factor of Λ

Cited by 35 publications

References 37 publications

Prospects for improvedΛcbranching fractions

Prospects for improvedΛcbranching fractions

Note on the slope parameter of the baryonic Λb→Λc Isgur–Wise function

Semileptonic decays of heavy baryons in the relativistic quark model

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