dorsal/arxiv
View SchemaCombined nonrelativistic constituent quark model and heavy quark effective theory study of semileptonic decays of \Lambda_b and \Xi_b baryons
| Authors | C. Albertus, E. Hernandez, J. Nieves |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0412006 |
| URL | https://arxiv.org/abs/nucl-th/0412006 |
| DOI | 10.1103/PhysRevD.71.014012 |
| Journal | Phys.Rev. D71 (2005) 014012 |
Abstract
We present the results of a nonrelativistic constituent quark model study of the semileptonic decays $\Lambda_b^0 \to \Lambda_c^+ l^- {\bar \nu}_l$ and $\Xi_b^0 \to \Xi_c^+ l^- {\bar \nu}_l$. We work on coordinate space, with baryon wave functions recently obtained from a variational approach based on heavy quark symmetry . We develop a novel expansion of the electroweak current operator, which supplemented with heavy quark effective theory constraints, allows us to predict the baryon form factors and the decay distributions for all $q^2$ (or equivalently $w$) values accessible in the physical decays. Our results for the partially integrated longitudinal and transverse decay widths, in the vicinity of the $w=1$ point, are in excellent agreement with lattice calculations. Comparison of our integrated $\Lambda_b-$decay width to experiment allows us to extract the $V_{cb}$ Cabbibo-Kobayashi-Maskawa matrix element for which we obtain a value of $|V_{cb}| = 0.040\pm 0.005 ({\rm stat}) ^{+0.001}_{-0.002} ({\rm theory})$ also in excellent agreement with a recent determination by the DELPHI Collaboration from the exclusive ${\bar {\rm B}^0_{\rm d}} \to {\rm D}^{*+}l^-{\bar \nu}_l$ decay. Besides for the $\Lambda_b (\Xi_b)-$decay, the longitudinal and transverse asymmetries, and the longitudinal to transverse decay ratio are $<a_L >=-0.954\pm 0.001 (-0.945\pm 0.002)$, $<a_T >=-0.665\pm 0.002 (-0.628\pm 0.004)$ and $R_{L/T}=1.63\pm 0.02 (1.53\pm 0.04)$, respectively.
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"abstract": "We present the results of a nonrelativistic constituent quark model study of\nthe semileptonic decays $\\Lambda_b^0 \\to \\Lambda_c^+ l^- {\\bar \\nu}_l$ and\n$\\Xi_b^0 \\to \\Xi_c^+ l^- {\\bar \\nu}_l$. We work on coordinate space, with\nbaryon wave functions recently obtained from a variational approach based on\nheavy quark symmetry . We develop a novel expansion of the electroweak current\noperator, which supplemented with heavy quark effective theory constraints,\nallows us to predict the baryon form factors and the decay distributions for\nall $q^2$ (or equivalently $w$) values accessible in the physical decays. Our\nresults for the partially integrated longitudinal and transverse decay widths,\nin the vicinity of the $w=1$ point, are in excellent agreement with lattice\ncalculations. Comparison of our integrated $\\Lambda_b-$decay width to\nexperiment allows us to extract the $V_{cb}$ Cabbibo-Kobayashi-Maskawa matrix\nelement for which we obtain a value of $|V_{cb}| = 0.040\\pm 0.005 ({\\rm stat})\n^{+0.001}_{-0.002} ({\\rm theory})$ also in excellent agreement with a recent\ndetermination by the DELPHI Collaboration from the exclusive ${\\bar {\\rm\nB}^0_{\\rm d}} \\to {\\rm D}^{*+}l^-{\\bar \\nu}_l$ decay. Besides for the\n$\\Lambda_b (\\Xi_b)-$decay, the longitudinal and transverse asymmetries, and the\nlongitudinal to transverse decay ratio are $\u003ca_L \u003e=-0.954\\pm 0.001 (-0.945\\pm\n0.002)$, $\u003ca_T \u003e=-0.665\\pm 0.002 (-0.628\\pm 0.004)$ and $R_{L/T}=1.63\\pm 0.02\n(1.53\\pm 0.04)$, respectively.",
"arxiv_id": "nucl-th/0412006",
"authors": [
"C. Albertus",
"E. Hernandez",
"J. Nieves"
],
"categories": [
"nucl-th",
"hep-ph"
],
"doi": "10.1103/PhysRevD.71.014012",
"journal_ref": "Phys.Rev. D71 (2005) 014012",
"title": "Combined nonrelativistic constituent quark model and heavy quark effective theory study of semileptonic decays of \\Lambda_b and \\Xi_b baryons",
"url": "https://arxiv.org/abs/nucl-th/0412006"
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