Conveners
Weak Decays and Matrix Elements
- Amarjit Soni
Weak Decays and Matrix Elements
- Weonjong Lee
Weak Decays and Matrix Elements
- Hiroshi Ohno
Weak Decays and Matrix Elements
- Takashi Kaneko
Weak Decays and Matrix Elements
- James Simone
Dr
Takashi Kaneko
(KEK)
14/07/2015, 16:30
Weak Decays and Matrix Elements
Talk
We present a study of the chiral behavior of light meson
form factors in QCD with three flavors of overlap quarks.
Gauge ensembles are generated at single lattice spacing 0.12fm
with pion masses down to 300 MeV. The pion and kaon
electro-magnetic form factors and the kaon semileptonic
form factors are precisely calculated using the all-to-all
quark propagator. We discuss their...
Prof.
Christopher Sachrajda
(University of Southampton)
14/07/2015, 16:50
Weak Decays and Matrix Elements
Talk
We review the method proposed in [1] to compute electromagnetic effects in
hadronic processes, such as decays, using lattice simulations. The method
can be applied, for example, to the leptonic and semileptonic decays of light
or heavy pseudoscalar mesons. For these quantities the presence of infrared
divergences in intermediate stages of the calculation makes the procedure
much more...
Dr
Renwick Hudspith
(York University, Toronto)
14/07/2015, 17:10
Weak Decays and Matrix Elements
Talk
We compute the hadronic matrix elements of the four-quark operators needed for the study of $K^0-{\bar K^0}$ mixing beyond the Standard Model (SM). We have used $n_f=2+1$ flavours of domain wall fermion (DWF) at two values of the lattice spacing ($a\approx0.08$ and $a\approx0.11\text{fm}$) and with lightest unitary Pion mass of $\approx300\,\text{MeV}$. Renormalisation is performed...
Mr
Jack Dragos
(University of Adelaide)
14/07/2015, 17:30
Weak Decays and Matrix Elements
Talk
Calculating hadronic matrix elements in Lattice QCD that are relevant for e.g. Form Factors and Parton Distribution Functions, provides important insights into the structure of hadrons. However standard 3-point function methods have their limitations. One of the most commonly studied sources of systematic error is excited state contamination, which occurs when correlators are contaminated with...
Dr
Thorsten Kurth
(Lawrence Berkeley National Laboratory)
14/07/2015, 17:50
Weak Decays and Matrix Elements
Talk
The electroweak interaction on the level of quarks and gluons are well understood from precision measurements in high energy collider experiments.
Relating these fundamental parameters to Hadronic Parity Violation in nuclei however remains an outstanding theoretical challenge. One of the most interesting observables in this respect is the parity violating hadronic neutral current: it is hard...
Tomomi Ishikawa
(RIKEN BNL Research Center)
16/07/2015, 08:30
Weak Decays and Matrix Elements
Talk
Neutral B meson mixing matrix elements and B meson decay constants are calculated in the infinite b quark mass limit. For the light quarks, domain-wall fermion (DWF) formalism is employed. The calculations are carried out using all-mode-averaging (AMA) technique on Nf=2+1 dynamical DWF ensembles with lattice spacings of nearly 0.08fm and 0.11fm, where pion masses are relatively heavy...
Prof.
Carleton DeTar
(University of Utah)
16/07/2015, 08:50
Weak Decays and Matrix Elements
Talk
We present preliminary, high-precision results for the decay constants
$f_B$ and $f_{B_s}$ from simulations with HISQ heavy and light valence
and sea quarks. Calculations are carried out with several heavy
valence-quark masses on ensembles with 2+1+1 flavors of HISQ sea
quarks at five lattice spacings and three light sea quark mass ratios
$m_{ud}/m_s$, including approximately physical...
Dr
James Simone
(Fermilab)
16/07/2015, 09:10
Weak Decays and Matrix Elements
Talk
We compute hadronic matrix elements for neutral $B$-meson mixing in
the Standard Model and beyond as well as the corresponding operators
for the the short-distance contribution to $D$-meson mixing. On the
same sets of gauge ensembles, we calculate the leptonic decay
constants for the $B$- and $D$-meson systems. The matrix elements are
computed with asqtad light quarks and clover heavy...
ran zhou
(Fermilab)
16/07/2015, 09:30
Weak Decays and Matrix Elements
Talk
We present Standard Model predictions for phenomenologically interesting observables for the rare decays $B \to K \ell^+\ell^-$, $B \to \pi \ell^+\ell^-$, $B \to K \nu \bar{\nu}$, and $B \to \pi \nu \bar{\nu}$, as well as for $B \to\pi\tau\nu$. All of these processes are sensitive to new physics effects, and there are a number of tensions between experimental measurements and Standard Model...
Dr
Brian Colquhoun
(University of Glasgow)
16/07/2015, 09:50
Weak Decays and Matrix Elements
Talk
Lattice NRQCD is a relatively inexpensive formalism that can be used to simulate b quarks on the lattice at their physical mass. The HPQCD collaboration has used radiatively-improved NRQCD for b quarks in bottomonium to determine the decay rate to leptons of the ground-sate Upsilon and its first radial excitation in lattice QCD. Using time moments of vector bottomonium current-current...
Mr
Justus Tobias Tsang
(University of Southampton, UK)
16/07/2015, 10:40
Weak Decays and Matrix Elements
Talk
This talk will provide an overview of RBC/UKQCD's charm project on their 2+1 flavour physical point ensembles using Moebius Domain Wall Fermions for the light as well as for the charm quark. I will discuss the analysis strategy and present first preliminary results for D and D_s decay constants.
Ms
Ava Khamseh
(Edinburgh University)
16/07/2015, 11:00
Weak Decays and Matrix Elements
Talk
We will report on the RBC/UKQCD charm project with (2+1)-flavor Domain Wall fermions at the physical point, and present progress on the determination of the matrix element of the VV+AA operator, and the Bag and Xi-parameters in the region of the physical charm quark mass. We will address the region of practical use of the domain wall action for heavy quark simulation and outline a strategy for...
Mr
Takashi Suzuki
(Osaka university)
16/07/2015, 11:20
Weak Decays and Matrix Elements
Talk
We report on our study of D meson semileptonic decays in QCD
with 2+1 flavors of the Moebius domain-wall fermions.
Gauge ensembles are generated at lattice cut-off around 2.4 GeV
and pion masses as low as 300 MeV. Relevant form factors are
calculated by using the Moebius action also for charm quarks.
Dr
Thomas Primer
(University of Arizona)
16/07/2015, 11:40
Weak Decays and Matrix Elements
Talk
We present a calculation of the $D\to\K,l,\nu$ and $D\to\pi,l,\nu$ semileptonic form factors at $q^2=0$.
These form factors are needed for the determination of the CKM matrix elements $\lvert{V_{cs}}\rvert$ and
$\lvert{V_{cd}}\rvert$ respectively.
This work uses the HISQ action for both valence quarks and sea quarks on MILC $N_f=2+1+1$ configurations, with ensembles including several at the...
Dr
Lorenzo Riggio
(INFN Roma Tre)
17/07/2015, 14:00
Weak Decays and Matrix Elements
Talk
We present lattice results for the form factors relevant for K -> pi l nu decays, obtained from simulations performed by the European Twisted Mass Collaboration with Nf=2+1+1 flavors of dynamical quarks, at three values of the lattice spacing and pion masses as low as 250 MeV.
Our determination of f_+(0), which in combination with the experimental result for (f_+(0)*V_us) can be used to...
Mr
Andrew Lawson
(University of Southampton)
17/07/2015, 14:20
Weak Decays and Matrix Elements
Talk
The rare decays of a kaon into a pion and a charged lepton/antilepton pair proceed via a flavour changing neutral current and therefore may only be induced beyond tree level in the Standard Model. This natural suppression makes these decays sensitive to the effects of potential New Physics. To discern such New Physics one must be able to control the errors on the Standard Model prediction of...
Dr
Xu Feng
(Columbia University)
17/07/2015, 14:40
Weak Decays and Matrix Elements
Talk
As flavor changing neutral current processes, rare kaon decays K -> pi nu nu-bar are highly suppressed in the standard model and thus provide ideal probes for the observation of new physics effects.
Given the importance of rare kaon decays, the CERN NA62 experiment aims at an observation of O(100) events of K+ -> pi+ nu nu-bar decay and a 10%-precision measurement of the branching ratio in...
Prof.
Norman Christ
(Columbia University)
17/07/2015, 15:00
Weak Decays and Matrix Elements
Talk
We will discuss the theoretical framework and initial results for the lattice QCD calculation of the long-distance contributions to $\epsilon_K$, the measure of indirect CP violation in $K_L$ decay. A proof-of-principle calculation has been carried out on a $24^3\times 64$ lattice volume with an inverse lattice spacing of 1.73 GeV and pion mass of 329 MeV. A complete calculation will be...
AMARJIT SONI
(Brookhaven National Lab)
17/07/2015, 15:20
Weak Decays and Matrix Elements
Talk
It has been been clear for past many years that in low energy observables new physics can only appear as a perturbation. Therefore precise theoretical predictions and precise experimental measurements have become rather mandatory. Here we draw attention to the significant advances that have been made on the lattice in recent years in K=> pi pi, Delta_M_K, long- distance part of epsilon_K and...
Michael Engelhardt
(NMSU)
17/07/2015, 15:40
Hadron Structure
Talk
An exploration of nucleon TMD observables at a substantially lower
pion mass, 170 MeV, than used in previous lattice TMD calculations
is presented. On a corresponding RBC/UKQCD DWF ensemble, TMDs are
extracted from nucleon matrix elements of a bilocal quark operator
containing a staple-shaped gauge link. Appropriate TMD ratios are
constructed to cancel divergences associated with the...
Dr
Taichi Kawanai
(Forschungszentrum Jülich GmbH)
17/07/2015, 16:30
Weak Decays and Matrix Elements
Talk
We report on updates of our $B$-physics program using domain-wall light quarks and nonperturbatively tuned, relativistic $b$-quarks by adding measurements obtained with dynamical and physical light quarks. We present progress towards improved determinations of the $B$-meson decay constant $f_B$, the ratio $f_{B_s}/f_B$, and the $B\to \pi \ell\nu$ semi-leptonic form factor. Our results are...
Mr
Edwin Lizarazo
(University of Southampton)
17/07/2015, 16:50
Weak Decays and Matrix Elements
Talk
We show first results for the computation of semi-leptonic form factors
for rare $B$ decays focusing in particular on $B \to K^{(*)} \ell^+ \ell^-$ and $B_s \to \phi \ell^+ \ell^-$. Our setup uses domain-wall light quarks, relativistic $b$ quarks, and the RBC/UKQCD 2+1 flavor gauge field configurations with domain-wall fermions and the Iwasaki gauge action.
Dr
Oliver Witzel
(University of Edinburgh)
17/07/2015, 17:10
Weak Decays and Matrix Elements
Talk
Using our well established setup of domain-wall light quarks and nonperturbatively tuned, relativistic $b$-quarks we extend our $B$-physics program to the computation of $B$-meson bag parameters and their ratio $\xi$. We present first results based on the RBC/UKQCD 2+1 flavor gauge field configurations with domain-wall fermions and the Iwasaki gauge action at two lattice spacing of 0.086 fm...
Dr
Antoine Gérardin
(Laboratoire de Physique Corpusculaire (LPC))
17/07/2015, 17:30
Weak Decays and Matrix Elements
Talk
We will present our results for the radial distributions of the axial density in the heavy-light B meson in the static limit of HQET: $\langle B(\vec{p}) | A_{\mu}(\vec{r}) | B^{*(\prime)}(\vec{p}^{\ \prime}, \lambda) \rangle$. Here, $r$ is the distance between the static heavy quark and the insertion of the axial current acting like a probe. Using the Generalized Eigenvalue Problem, we are...
