caa a22 4500 445873272 CHVBK 20180317145519.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1140/epja/i2011-11147-7 doi (NATIONALLICENCE)springer-10.1140/epja/i2011-11147-7 Implications of unitarity and analyticity for the Dπ form factors [Elektronische Daten] [B. Ananthanarayan, I. Caprini, I. Sentitemsu Imsong] We consider the vector and scalar form factors of the charm-changing current responsible for the semileptonic decay D → πlν. Using as input dispersion relations and unitarity for the moments of suitable heavy-light correlators evaluated with Operator Product Expansions, including O(α s 2 ) terms in perturbative QCD, we constrain the shape parameters of the form factors and find exclusion regions for zeros on the real axis and in the complex plane. For the scalar form factor, a low-energy theorem and phase information on the unitarity cut are also implemented to further constrain the shape parameters. We finally propose new analytic expressions for the Dπ form factors, derive constraints on the relevant coefficients from unitarity and analyticity, and briefly discuss the usefulness of the new parametrizations for describing semileptonic data. SIF, Springer-Verlag Berlin Heidelberg, 2011 Ananthanarayan B. Centre for High Energy Physics, Indian Institute of Science, 560 012, Bangalore, India aut Caprini I. Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125, Magurele, Romania aut Sentitemsu Imsong I. Centre for High Energy Physics, Indian Institute of Science, 560 012, Bangalore, India aut The European Physical Journal A Springer Berlin Heidelberg 47/11(2011-11-01), 1-10 1434-6001 47:11<1 2011 47 10050 https://doi.org/10.1140/epja/i2011-11147-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1140/epja/i2011-11147-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ananthanarayan B. Centre for High Energy Physics, Indian Institute of Science, 560 012, Bangalore, India aut NATIONALLICENCE 700 1- Caprini I. Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125, Magurele, Romania aut NATIONALLICENCE 700 1- Sentitemsu Imsong I. Centre for High Energy Physics, Indian Institute of Science, 560 012, Bangalore, India aut NATIONALLICENCE 773 0- The European Physical Journal A Springer Berlin Heidelberg 47/11(2011-11-01), 1-10 1434-6001 47:11<1 2011 47 10050 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer