{ "id": "hep-ph/0210231", "version": "v2", "published": "2002-10-16T14:29:45.000Z", "updated": "2002-11-06T16:42:56.000Z", "title": "Bounds on the derivatives of the Isgur-Wise function from sum rules in the heavy quark limit of QCD", "authors": [ "A. Le Yaouanc", "L. Oliver", "J. -C. Raynal" ], "comment": "9 pages, Latex", "journal": "Phys.Lett. B557 (2003) 207-212", "doi": "10.1016/S0370-2693(03)00180-1", "categories": [ "hep-ph" ], "abstract": "Using the OPE and the trace formalism, we have obtained a number of sum rules in the heavy quark limit of QCD that include the sum over all excited states for any value $j^P$ of the light cloud. We show that these sum rules imply that the elastic Isgur-Wise function $\\xi (w)$ is an alternate series in powers of $(w-1)$. Moreover, we obtain sum rules involving the derivatives of the elastic Isgur-Wise function $\\xi (w)$ at zero recoil, that imply that the $n$-th derivative can be bounded by the $(n-1)$-th one. For the curvature $\\sigma^2 = \\xi''(1)$, this proves the already proposed bound $\\sigma^2 \\geq {5 \\over 4} \\rho^2$. Moreover, we obtain the absolute bound for the $n$-th derivative $(-1)^n \\xi^{(n)}(1) \\geq {(2n+1)!! \\over 2^{2n}}$, that generalizes the results $\\rho^2 \\geq {3 \\over 4}$ and $\\sigma^2 \\geq {15 \\over 16}$.", "revisions": [ { "version": "v2", "updated": "2002-11-06T16:42:56.000Z" } ], "analyses": { "keywords": [ "heavy quark limit", "sum rules", "elastic isgur-wise function", "th derivative", "light cloud" ], "tags": [ "journal article" ], "note": { "typesetting": "LaTeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable", "inspire": 599935 } } }