### Abstract

We present a lattice QCD calculation of form factors for the decay Λ_{b}→pμ^{-}ν_{̄μ}, which is a promising channel for determining the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}| at the Large Hadron Collider. In this initial study we work in the limit of static b quarks, where the number of independent form factors reduces to two. We use dynamical domain-wall fermions for the light quarks, and perform the calculation at two different lattice spacings and at multiple values of the light-quark masses in a single large volume. Using our form factor results, we calculate the Λ_{b}→pμ ^{-}ν_{̄μ} differential decay rate in the range 14 GeV2≤q2≤qmaxâ¡2, and obtain the integral ∫14 GeV2qmaxâ¡2[dΓ/dq2]dq2/|V_{ub}|2=15.3±4.2 ps^{-}1. Combined with future experimental data, this will give a novel determination of |V_{ub}| with about 15% theoretical uncertainty. The uncertainty is dominated by the use of the static approximation for the b quark, and can be reduced further by performing the lattice calculation with a more sophisticated heavy-quark action.

Original language | English (US) |
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Article number | 014512 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 88 |

Issue number | 1 |

DOIs | |

State | Published - Jul 23 2013 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Nuclear and High Energy Physics

### Cite this

_{b}→pℓ-ν

_{̄ℓ}form factors from lattice QCD with static b quarks.

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*88*(1), [014512]. https://doi.org/10.1103/PhysRevD.88.014512

**Λ _{b}→pℓ-ν_{̄ℓ} form factors from lattice QCD with static b quarks.** / Detmold, William; Lin, C. J David; Meinel, Stefan; Wingate, Matthew.

Research output: Contribution to journal › Article

_{b}→pℓ-ν

_{̄ℓ}form factors from lattice QCD with static b quarks',

*Physical Review D - Particles, Fields, Gravitation and Cosmology*, vol. 88, no. 1, 014512. https://doi.org/10.1103/PhysRevD.88.014512

_{b}→pℓ-ν

_{̄ℓ}form factors from lattice QCD with static b quarks. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2013 Jul 23;88(1). 014512. https://doi.org/10.1103/PhysRevD.88.014512

}

TY - JOUR

T1 - Λb→pℓ-ν̄ℓ form factors from lattice QCD with static b quarks

AU - Detmold, William

AU - Lin, C. J David

AU - Meinel, Stefan

AU - Wingate, Matthew

PY - 2013/7/23

Y1 - 2013/7/23

N2 - We present a lattice QCD calculation of form factors for the decay Λb→pμ-ν̄μ, which is a promising channel for determining the Cabibbo-Kobayashi-Maskawa matrix element |Vub| at the Large Hadron Collider. In this initial study we work in the limit of static b quarks, where the number of independent form factors reduces to two. We use dynamical domain-wall fermions for the light quarks, and perform the calculation at two different lattice spacings and at multiple values of the light-quark masses in a single large volume. Using our form factor results, we calculate the Λb→pμ -ν̄μ differential decay rate in the range 14 GeV2≤q2≤qmaxâ¡2, and obtain the integral ∫14 GeV2qmaxâ¡2[dΓ/dq2]dq2/|Vub|2=15.3±4.2 ps-1. Combined with future experimental data, this will give a novel determination of |Vub| with about 15% theoretical uncertainty. The uncertainty is dominated by the use of the static approximation for the b quark, and can be reduced further by performing the lattice calculation with a more sophisticated heavy-quark action.

AB - We present a lattice QCD calculation of form factors for the decay Λb→pμ-ν̄μ, which is a promising channel for determining the Cabibbo-Kobayashi-Maskawa matrix element |Vub| at the Large Hadron Collider. In this initial study we work in the limit of static b quarks, where the number of independent form factors reduces to two. We use dynamical domain-wall fermions for the light quarks, and perform the calculation at two different lattice spacings and at multiple values of the light-quark masses in a single large volume. Using our form factor results, we calculate the Λb→pμ -ν̄μ differential decay rate in the range 14 GeV2≤q2≤qmaxâ¡2, and obtain the integral ∫14 GeV2qmaxâ¡2[dΓ/dq2]dq2/|Vub|2=15.3±4.2 ps-1. Combined with future experimental data, this will give a novel determination of |Vub| with about 15% theoretical uncertainty. The uncertainty is dominated by the use of the static approximation for the b quark, and can be reduced further by performing the lattice calculation with a more sophisticated heavy-quark action.

UR - http://www.scopus.com/inward/record.url?scp=84881292878&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84881292878&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.88.014512

DO - 10.1103/PhysRevD.88.014512

M3 - Article

VL - 88

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 0556-2821

IS - 1

M1 - 014512

ER -