### Resumé

Originalsprog | Udefineret/Ukendt |
---|---|

Tidsskrift | PoS ICHEP |

Status | Udgivet - 27. nov. 2012 |

### Emneord

- hep-lat

### Citer dette

*PoS ICHEP*.

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*PoS ICHEP*.

**$|V_{ub}|$ determination in lattice QCD.** / Bahr, F.; Bernardoni, F.; Blossier, B.; Bulava, J.; Morte, M. Della; Fritzsch, P.; Garron, N.; Gérardin, A.; Heitger, J.; Hippel, G. von; Ramos, A.; Simma, H.; Sommer, R.

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

TY - JOUR

T1 - $|V_{ub}|$ determination in lattice QCD

AU - Bahr, F.

AU - Bernardoni, F.

AU - Blossier, B.

AU - Bulava, J.

AU - Morte, M. Della

AU - Fritzsch, P.

AU - Garron, N.

AU - Gérardin, A.

AU - Heitger, J.

AU - Hippel, G. von

AU - Ramos, A.

AU - Simma, H.

AU - Sommer, R.

PY - 2012/11/27

Y1 - 2012/11/27

N2 - The 2012 PDG reports a tension at the level of $3 \sigma$ between two exclusive determinations of $|V_{ub}|$. They are obtained by combining the experimental branching ratios of $B \to \tau \nu$ and $B \to \pi l \nu$ (respectively) with a theoretical computation of the hadronic matrix elements $\fB$ and the $B \to \pi$ form factor $f_+(q^2)$. To understand the tension, improved precision and a careful analysis of the systematics involved are necessary. We report the results of the ALPHA collaboration for $\fB$ from the lattice with 2 flavors of $O(a)$ improved Wilson fermions. We employ HQET, including $1/m_b$ corrections, with pion masses ranging down to $\approx$ 190 MeV. Renormalization and matching were performed non-perturbatively, and three lattice spacings reaching $a^{-1}\approx 4.1$ GeV are used in the continuum extrapolation. We also present progress towards a computation of $f_+(q^2)$, to directly compare two independent exclusive determinations of $|V_{ub}|$ with each other and with inclusive determinations. Additionally, we report on preliminary results for $\fBq{s}$, needed for the analysis of $B_s \to \mu^+\mu^-$.}

AB - The 2012 PDG reports a tension at the level of $3 \sigma$ between two exclusive determinations of $|V_{ub}|$. They are obtained by combining the experimental branching ratios of $B \to \tau \nu$ and $B \to \pi l \nu$ (respectively) with a theoretical computation of the hadronic matrix elements $\fB$ and the $B \to \pi$ form factor $f_+(q^2)$. To understand the tension, improved precision and a careful analysis of the systematics involved are necessary. We report the results of the ALPHA collaboration for $\fB$ from the lattice with 2 flavors of $O(a)$ improved Wilson fermions. We employ HQET, including $1/m_b$ corrections, with pion masses ranging down to $\approx$ 190 MeV. Renormalization and matching were performed non-perturbatively, and three lattice spacings reaching $a^{-1}\approx 4.1$ GeV are used in the continuum extrapolation. We also present progress towards a computation of $f_+(q^2)$, to directly compare two independent exclusive determinations of $|V_{ub}|$ with each other and with inclusive determinations. Additionally, we report on preliminary results for $\fBq{s}$, needed for the analysis of $B_s \to \mu^+\mu^-$.}

KW - hep-lat

M3 - Tidsskriftartikel

JO - PoS ICHEP

JF - PoS ICHEP

ER -