# $|V_{ub}|$ determination in lattice QCD

F. Bahr, F. Bernardoni, B. Blossier, J. Bulava, M. Della Morte, P. Fritzsch, N. Garron, A. Gérardin, J. Heitger, G. von Hippel, A. Ramos, H. Simma, R. Sommer

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

### Resumé

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 $B_s \to \mu^+\mu^-$.}
Originalsprog Udefineret/Ukendt PoS ICHEP Udgivet - 27. nov. 2012

• hep-lat

### Citer dette

Bahr, F., Bernardoni, F., Blossier, B., Bulava, J., Morte, M. D., Fritzsch, P., ... Sommer, R. (2012). $|V_{ub}|$ determination in lattice QCD. PoS ICHEP.
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. / $|V_{ub}|$ determination in lattice QCD. I: PoS ICHEP. 2012.
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title = "$|V_{ub}|$ determination in lattice QCD",
abstract = "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 $B_s \to \mu^+\mu^-$.}",
keywords = "hep-lat",
author = "F. Bahr and F. Bernardoni and B. Blossier and J. Bulava and Morte, {M. Della} and P. Fritzsch and N. Garron and A. G{\'e}rardin and J. Heitger and Hippel, {G. von} and A. Ramos and H. Simma and R. Sommer",
year = "2012",
month = "11",
day = "27",
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journal = "PoS ICHEP",

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Bahr, F, Bernardoni, F, Blossier, B, Bulava, J, Morte, MD, Fritzsch, P, Garron, N, Gérardin, A, Heitger, J, Hippel, GV, Ramos, A, Simma, H & Sommer, R 2012, '$|V_{ub}|$ determination in lattice QCD', 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.

I: PoS ICHEP, 27.11.2012.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer 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 -

Bahr F, Bernardoni F, Blossier B, Bulava J, Morte MD, Fritzsch P et al. $|V_{ub}|$ determination in lattice QCD. PoS ICHEP. 2012 nov 27.