Dr
Jack Dragos
(FRIB NSCL MSU)

7/24/18, 2:00 PM

Weak Decays and Matrix Elements

Parallel

We utilize the gradient flow to define and calculate electric dipole moments (EDMs) induced by the
strong QCD $\theta$-term.
Since the EDM is highly sensitive to the CP-violating operator induced in the action,
the Euclidean time dependence of the topological charge is utilized to improve the signal to noise.
The results of the nucleon EDMs are calculated on PACS-CS gauge fields...

Dr
Jangho Kim
(NSCL & Michigan State University)

7/24/18, 2:20 PM

Weak Decays and Matrix Elements

Parallel

The quark-chrom EDM (qCEDM) is a dimension 5 operator parametrizing at low energy BSM contributions to a non-vanishing EDM.
We discuss the implementation of the qCEDM with the gradient flow and show preliminary results for the flow-time dependence of the CP-violating mixing angle $\alpha_N$ induced by the qCEDM between nucleon states.
These results are computed on the $N_f=2+1$ coarse...

Dr
William Detmold
(MIT)

7/24/18, 2:40 PM

Weak Decays and Matrix Elements

Parallel

I will discuss recent calculations of the matrix elements of scalar, axial and tensor quark bilinear operators in light nuclei at unphysically heavy values of the quark masses. Axial matrix elements control the Gamow-Teller decays of nuclei and have potential for precision tests of the Standard Model. Tensor matrix elements determine the quark chromo-electric dipole moment and are important in...

Dr
David Murphy
(MIT)

7/24/18, 3:00 PM

Weak Decays and Matrix Elements

Parallel

While neutrino oscillation experiments have demonstrated that neutrinos have small, nonzero masses, much remains unknown about their properties and decay modes. One potential decay mode --- neutrinoless double beta decay ($0 \nu \beta \beta$) --- is a particularly interesting target of experimental searches, since its observation would imply both the violation of lepton number conservation in...

Henry Monge-Camacho
(College of William and Mary, LBNL)

7/24/18, 3:20 PM

Weak Decays and Matrix Elements

Parallel

A strong candidate to search for new physics Beyond the Standard Model is neutrinoless double beta decay. Observation of this very rare nuclear process which violates lepton number conservation, would imply the neutrino sector has a majorana mass component and may also provide an explanation for universe's matter-antimatter asymmetry. In the case a heavy majorana neutrino is exchanged in this...

Prof.
Aida El-Khadra
(University of Illinois at Urbana-Champaign)

7/25/18, 2:00 PM

Weak Decays and Matrix Elements

Parallel

Using HISQ $N_f=2+1+1$ MILC ensembles at five different lattice spacings, including four ensembles with physical quark masses, we perform the most precise computation to date of the $K\to\pi\ell\nu$ vector form factor at zero momentum transfer. This is the first calculation that includes the dominant finite-volume effects, as calculated in chiral perturbation theory at next-to-leading order....

Mr
Junpei Kakazu
(Univ. of Tsukuba)

7/25/18, 2:20 PM

Weak Decays and Matrix Elements

We present our preliminary result of the form factor of $K \to \pi l \nu$
semileptonic decays on the large volume configuration, $L \approx 10$ fm,
with the physical $m_{\pi}$ and $m_{K}$ using the stout-smearing
clover quark and Iwasaki gauge actions at $a^{-1}=2.333$ GeV.
From an interpolation using the data in small momentum transfers,
we determine the semileptonic decay form factors...

Prof.
Chris Sachrajda
(University of Southampton)

7/25/18, 2:40 PM

Weak Decays and Matrix Elements

The precision of lattice QCD computations of many quantities have reached such a precision that isospin breaking corrections, including electromagnetism, must be included if further progress is to be made in extracting fundamental information, such as the values of Cabibbo-Kobayashi-Maskawa matrix elements, from experimental measurements. I discuss the framework for including radiative...

Mr
James Richings
(University of Southampton)

7/25/18, 3:00 PM

Weak Decays and Matrix Elements

Predictions for pion and kaon leptonic decay constants in Lattice QCD have reached sub-percent level precision. Since it is expected that isospin breaking corrections become important at this level of precision, further progress on the lattice requires inclusion of these effects. Given the phenomenological relevance for instance in CKM analyses this seems a worthwhile endeavour. In this talk I...

Sophie Hollitt
(University of Adelaide)

7/25/18, 3:20 PM

Weak Decays and Matrix Elements

Early B physics experiments have left us with a number of puzzles in heavy flavour physics. New lattice calculations and greater understanding of QCD effects in the Standard Model will be needed to support greater experimental precision in the coming years. In particular, the B meson decay constant is involved in calculations of CKM matrix elements and useful to measurements of the branching...

Dr
Ruizi Li
(Indiana University)

7/26/18, 8:30 AM

Weak Decays and Matrix Elements

We calculate $D \rightarrow Kl\nu, \pi l\nu$ vector form factors $f_+^{K/\pi}$ at zero-momentum transfer, using MILC's $N_f = 2+1+1$ HISQ ensembles at four lattice spacings, $a \approx 0.042, 0.06, 0.09, 0.12$ fm, and various HISQ quark masses down to the (degenerate) physical light quark mass. We use the kinematic constraint $f_+= f_0$ at $q^2 = 0$ to determine the vector form factor from our...

Dr
Andrea Bussone
(IFT, UAM-CSIC)

7/26/18, 8:50 AM

Weak Decays and Matrix Elements

We introduce a mixed-action approach based on CLS ensembles, where a valence Nf=2+1+1 fully-twisted tmQCD action is combined with the Nf=2+1 non-perturbatively O(a)-improved Wilson sea sector. Some field-theoretical properties of this setup (unitarity, O(a) improvement, relevance of open boundary conditions) are discussed. Particular emphasis is given to the application of this setup to...

Mr
Javier Ugarrio
(IFT, UAM-CSIC)

7/26/18, 9:10 AM

Weak Decays and Matrix Elements

We present first preliminary results for masses and decay constants of charmed mesons using a valence Nf=2+1+1 fully-twisted tmQCD action combined with an Nf=2+1 non-perturbatively O(a)-improved Wilson sea sector. The impact of various techniques to reduce noise and improve spectroscopic resolution is presented, and the scaling of basic observables towards the continuum limit explored in a...

Dr
J Tobias Tsang
(University of Edinburgh)

7/26/18, 9:30 AM

Weak Decays and Matrix Elements

I will present a status update of RBC/UKQCD's charm (to bottom) physics program based on ensembles with $N_f=2+1$ flavours of domain wall fermions featuring physical pion masses.
After a brief review of our program, the main focus will be on mesonic decay constants and neutral meson mixing in the charm and bottom sector, where results for the bottom sector are obtained from an extrapolation...

Dr
Giorgio Salerno
(University of Roma Tre & LPT Orsay)

7/26/18, 9:50 AM

Weak Decays and Matrix Elements

We present a preliminary lattice determination of the masses and decay constants of the pseudoscalar and vector mesons $B_c$ and $B_c^*$. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with $N_f=2+1+1$ flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV....

Dr
Brian Colquhoun
(KEK)

7/26/18, 10:10 AM

Weak Decays and Matrix Elements

We report on the progress of our calculation of form factors for the exclusive semileptonic decay of B mesons to pions on $2+1$ flavour lattices with spacings from $0.080~\mathrm{fm}$ down to $0.044~\mathrm{fm}$. Using the Mobius domain wall fermion action for all quarks, we simulate pions with masses down 230 MeV over a range of momenta, and extrapolate to the bottom quark mass by utilising...

Prof.
Robert Mawhinney
(Columbia University)

7/26/18, 11:00 AM

Weak Decays and Matrix Elements

The RBC and UKQCD Collaborations have generated a number
of coarse ensembles with 2+1 flavors of Mobius Domain Wall Fermions
(MDWF) and physical quark masses using the Iwasaki plus Dislocation
Suppressing Determinant Ratio (DSDR) action. Previous work has
shown small $O(a^2)$ scaling violations for pseudoscalar decay
constants, various masses and Wilson flow scales. In this talk,
we...

Mr
Tianle Wang
(Columbia University)

7/26/18, 11:20 AM

Hadron Spectroscopy and Interactions

We report a direct lattice calculation of both the I=0 and 2 pi-pi scattering phase shifts using G-parity boundary conditions on an ensemble of $32^3\times64$ gauge configurations at physical quark mass. This extends an earlier calculation of the RBC/UKQCD Collaboration by including additional operators and using non-zero center-of-mass momenta. We apply the generalized eigenvalue treatment...

Dr
Christopher Kelly
(Columbia University)

7/26/18, 11:40 AM

Weak Decays and Matrix Elements

We provide an update on the RBC & UKQCD lattice calculation of the measure of Standard Model direct CP-violation in kaon decays, \epsilon'

Mr
Fernando Romero-Lopez
(University of Valencia, IFIC)

7/26/18, 12:00 PM

Weak Decays and Matrix Elements

In this work we present our latest results about the K $\to$ $\pi$ matrix elements at large $N_c$, including the exploration of the mass dependence and the latest simulations with $N_f=4$ dynamical fermions.

Prof.
Xu Feng
(Peking University)

7/26/18, 12:20 PM

Weak Decays and Matrix Elements

In this talk, we present our progress on the study of the electromagnetic corrections to $K\to\pi\pi$ decay. To provide an accurate Standard-Model determination of direct CP violation at the precision of O(10%), it is important to include the electromagnetic corrections, as such $O(\alpha_e)$ effects could be enhanced 22 times in principle due to the isospin mixing and the $\Delta I=1/2$ rule....

Mr
Yiming Cai
(University of Maryland, College Park)

7/26/18, 12:40 PM

Weak Decays and Matrix Elements

A precise Standard Model prediction for the direct CP violation in the K -> \pi\pi decay process is of great importance in confronting experiments and constraining new physics. The state-of-art lattice QCD precision of this process will soon achieve a value for which QED effects can no longer be neglected. The inclusion of QED in such calculations is planned and the formalism to relate the...

Mr
Euan McLean
(University of Glasgow)

7/27/18, 2:00 PM

Weak Decays and Matrix Elements

We present progress on an ongoing calculation of the $B_s\to D_s l\nu$ form factors
calculated on the 2+1+1 MILC ensembles and using the Highly Improved Staggered Quark action for all valence quarks. We perform the calculation at unphysically light $b$ quark masses and
extrapolate to the physical point.

Dr
Alejandro Vaquero
(University of Utah)

7/27/18, 2:20 PM

Weak Decays and Matrix Elements

We present preliminary blinded results from our analysis of the form factors for B¯→D⋆ℓν¯ decay at non-zero recoil. Our analysis includes 15 MILC asqtad ensembles with Nf=2+1 flavors of sea quarks and lattice spacings ranging from a≈0.15 fm down to 0.045 fm. The valence light quarks employ the asqtad action, whereas The b and c quarks are treated using the Fermilab action. We discuss the...

Dr
Sungwoo Park
(Los Alamos National Laboratory)

7/27/18, 2:40 PM

Weak Decays and Matrix Elements

We update the calculation of $B \to D^\ast \ell \nu$ form factor at zero-recoil using the Oktay-Kronfeld (OK) action for bottom and charm quarks. Heavy quark action is nonperturbatively tuned. The flavor changing currents are improved to $\mathcal{O}(\lambda\approx \Lambda_{QCD}/2m_Q)$, $Q=b,c$ at tree-level in the HQET power counting. We use the HISQ action for the light spectator quark with...

Prof.
Weonjong Lee
(Seoul National University)

7/27/18, 3:00 PM

Weak Decays and Matrix Elements

We report recent progress in determining $\varepsilon_K$, the indirect
CP violation parameter in the neutral kaon system, calculated using
lattice QCD inputs including $B_K$, $\xi_0$, $\xi_2$, $V_{us}$,
$V_{cb}$, and $m_c(m_c)$. In this report, various other input
parameters such as $m_t(m_t)$ have also been updated recently.

Ms
Julia Kettle
(University of Edinburgh)

7/27/18, 3:20 PM

Weak Decays and Matrix Elements

I present an update on the calculation of beyond the standard model kaon mixing matrix elements in isospin symmetric pure QCD with $n_f$ = 2 + 1 dynamical flavours calculated with data at the physical pion mass. Our analysis includes simulations with domain wall fermions and an Iwasaki gauge, at three-lattice spacings and a range of pion masses from the physical point up to 430 MeV.
We...

Mr
Bigeng Wang
(Columbia University)

7/27/18, 3:40 PM

Weak Decays and Matrix Elements

The two neutral kaon states in nature, the KL (long-lived) and KS (short-lived) mesons, are the two time-evolution eigenstates of the $K^0$ -- $\overline{K}^0$ mixing system. The prediction of their mass difference $\Delta M_K$ based on the Standard Model is an important goal of lattice QCD. In this talk, I will present preliminary results from a calculation of $\Delta M_K$ performed on an...

Dr
Lorenzo Riggio
(INFN Sez. Roma Tre)

7/27/18, 4:30 PM

Weak Decays and Matrix Elements

We present a preliminary study toward a lattice determination of the vector
and scalar form factors of the $B \to \pi \ell \nu$ semileptonic decays.
We compute the form factors relative to the transition between pseudo-scalar
heavy mesons, with masses above the D-mass, and the pion. We simulate the
valence heavy quark with a mass in the range $ m_c < m_h < 2m_c $.
Lorentz symmetry...

Christopher Bouchard
(Ohio State)

7/27/18, 4:50 PM

Weak Decays and Matrix Elements

We discuss a calculation of the form factors for the flavor-changing charged current $b\to u$ and the flavor-changing neutral current $b\to d$ semileptonic decays, $B\to \pi\ell\nu$ and $B\to\pi\ell\ell$. HISQ light and NRQCD $b$ valence quarks are simulated on the MILC $N_f=2+1$ asqtad ensembles, including pion momenta that cover the full kinematic range of the decay. These data are...

Mr
Zechariah Gelzer
(University of Iowa)

7/27/18, 5:10 PM

Weak Decays and Matrix Elements

We report the status of an ongoing lattice-QCD calculation of form factors
for exclusive semileptonic decays of $B$~mesons with both charged currents
($B\to\pi\ell\nu$, $B_s\to K\ell\nu$) and neutral currents
($B\to\pi\ell^+\ell^-$, $B\to K\ell^+\ell^-$). The results are important for
constraining or revealing physics beyond the Standard Model. This work uses
MILC's (2+1+1)-flavor...

Oliver Witzel Witzel
(University of Colorado Boulder)

7/27/18, 5:30 PM

Weak Decays and Matrix Elements

We report on our determination of form factors for Bs semi-leptonic decays and extract ratios to investigate lepton flavor universality violations. Our calculation is based on RBC-UKQCD's gauge field ensembles featuring 2+1 flavors of domain-wall fermions and Iwasaki gauge action at three lattice spacing of 1/a = 1.78, 2.38, and 2.77 GeV. In the valence sector we use domain-wall light,...

Mr
Erik Gustafson
(University of Iowa)

7/27/18, 5:50 PM

Weak Decays and Matrix Elements

We present a method of examining the efficacy of different formulations of the z-expansion in semileptonic B decays. We examine three different parameterizations of the z-expansion, the BGL, BCL and a recent Padé expansion. Our method involves fitting these parameterizations to the large momentum transfer data ($q^2$ > $17 ~GeV^2$) and seeing how well these parameterizations predict the low...

Amarjit Soni
(BNL)

7/27/18, 6:10 PM

Weak Decays and Matrix Elements

In the past few years several observables are indicating deviations from the SM amounting to a few sigmas. In view of the experimental developments on the horizon and bearing in mind recent advances in matrix elements calculations, in this talk I will discuss ways in which lattice methods may be used to improve precision in the predictions of the SM so that the experimental data can be used...