Review of recent developments on leptonic and semileptonic charm - - PowerPoint PPT Presentation

▶
review of recent developments on leptonic and
SMART_READER_LITE
LIVE PREVIEW

Review of recent developments on leptonic and semileptonic charm - - PowerPoint PPT Presentation

Apr 11, 2024 179 likes •555 views

CHARM 2018 CHARM 2018 Review of recent developments on leptonic and semileptonic charm decays from lattice QCD Universit di Roma Tre, INFN Roma Tre, LPT Orsay Universit di Roma Tre, INFN Roma Tre, LPT Orsay Lattjce QCD Non-perturbative

slide-1
SLIDE 1

Review of recent developments on leptonic and semileptonic charm decays from lattice QCD

CHARM 2018 CHARM 2018 Università di Roma Tre, INFN Roma Tre, LPT Orsay Università di Roma Tre, INFN Roma Tre, LPT Orsay

slide-2
SLIDE 2

Lattjce QCD

1/23 Giorgio Salerno CHARM 2018

✦ Discrete Euclidean Space-Time ✦ Finite spatial volume and time extent

Non-perturbative QCD contributions from fjrst principles Control all systematic uncertainties

✦ Path integrals rigorously defjned and

computed via Monte Carlo methods

slide-3
SLIDE 3

Lattjce QCD

2/23 Giorgio Salerno CHARM 2018

✦ Finite volume and time:

Non-perturbative QCD contributions from fjrst principles Control all systematic uncertainties

✦ Quark masses:

Parameters in a simulation:

✦ # see quarks: ✦ Lattice spacing:

slide-4
SLIDE 4

Lattjce QCD

3/23 Giorgio Salerno CHARM 2018

QCD recovered by removing cutofgs

✦ Continuum limit: ✦ Interpolation/Extrapolation

to physical quark masses: Infjnite volume limit:

✦ T

  • reliably estimate systematic errors:

repeat the calculation for several lattice spacing, volumes and sea-quark masses

slide-5
SLIDE 5

Lattjce QCD - State of the art

4/23 Giorgio Salerno CHARM 2018

[G. Herdoiza summer 2015 + (partial) updates, C. Pena]

slide-6
SLIDE 6

Quark masses on the lattjce

5/23 Giorgio Salerno CHARM 2018

  • Bottom quarks:

Heavy quarks: discretization errors

  • Charm quarks:

directly accessible on the lattice extrapolation or an efgective theory (HQET, NRQCD, ...) is needed

Light quarks: discretization errors

fjnite size efgects

Extrapolation in mu,d often necessary (ChPT)

slide-7
SLIDE 7

Euclidean Correlators

Masses and hadronic matrix elements are extracted from Euclidean Correlators

7/21 Giorgio Salerno CHARM 2018 6/23

slide-8
SLIDE 8

Leptonic decays

1/22 Giorgio Salerno LATTICE 2017

CKM matrix elements Decay constants (Lattice QCD) Decay rate (Experiments)

  • Experimental + LQCD inputs for the determination of CKM elements
  • Systematic and statistical errors cancellation in the SU(3) ratio

7/23 Giorgio Salerno CHARM 2018

slide-9
SLIDE 9

Leptonic decays - FLAG

1/22 Giorgio Salerno LATTICE 2017

FNAL/MILC 14A

  • Improved action
  • Physical mass:
  • ETM 14E
  • Physical mass:
  • 8/23

Giorgio Salerno CHARM 2018

  • Improved action
slide-10
SLIDE 10

Leptonic decays – New Results

1/22 Giorgio Salerno LATTICE 2017

RBC/UKQCD

  • Physical mass:
  • 9/23
  • DW fermions
  • CHARM 2018

Giorgio Salerno

slide-11
SLIDE 11

Leptonic decays – New Results

1/22 Giorgio Salerno LATTICE 2017

RBC/UKQCD

10/23 CHARM 2018 Giorgio Salerno

slide-12
SLIDE 12

Leptonic decays – New Results

1/22 Giorgio Salerno LATTICE 2017

  • FNAL/MILC
  • down to
  • 20 ensembles

Giorgio Salerno CHARM 2018

  • Big volumes (up to: 1443 x 288, 6 fm)
  • Very high statistics (1000x4 samples)
  • Light-quark mass down to

11/23

slide-13
SLIDE 13

Leptonic decays – New Results

1/22 Giorgio Salerno LATTICE 2017 Giorgio Salerno CHARM 2018

FNAL/MILC

12/23

slide-14
SLIDE 14

Semileptonic decays

1/22 Giorgio Salerno LATTICE 2017

  • Experimental + LQCD inputs for the determination of CKM elements
  • Determination of the forms factors in all the physical q2 range

CKM matrix elements Form factors (Lattice QCD)

  • Momentum dependence of the tensor form factor for BSM analysis

Giorgio Salerno CHARM 2018 13/23

slide-15
SLIDE 15

Semileptonic decays - FLAG

1/22 Giorgio Salerno LATTICE 2017

HPQCD

  • Improved action
  • D at rest frame
  • Physical mass:
  • No renormalization
  • Modifjed z-expansion
  • fmavors of HISQ
  • f0 from the Scalar matrix element

Giorgio Salerno CHARM 2018 14/23

slide-16
SLIDE 16

Semileptonic decays - New Results

Giorgio Salerno LATTICE 2017

HPQCD

  • Improved action
  • D at rest frame
  • Physical mass:
  • No renormalization
  • Modifjed z-expansion
  • fmavors of HISQ
  • f0 from the Scalar matrix element

Giorgio Salerno CHARM 2018

New (Preliminary) (B. Chakraborty) @ LATTICE 2017

  • Physical u/d quarks
  • Both f+ and f0 over whole q2-range

15/23

slide-17
SLIDE 17

Semileptonic decays - New Results

Giorgio Salerno LATTICE 2017

ETMC

  • Improved action
  • f+,0 and fT over whole q2-range
  • Physical mass:
  • No renormalization
  • Hypercubic discretization efgects
  • fmavors of tmW
  • Modifjed z-expansion
  • Vector & Scalar matrix elements

Giorgio Salerno CHARM 2018 16/23

slide-18
SLIDE 18

f 0(q2) and f +(q2) at the physical point

Semileptonic decays - New Results

Giorgio Salerno CHARM 2018

ETMC

17/23

slide-19
SLIDE 19

Semileptonic decays - New Results

1/22 Giorgio Salerno LATTICE 2017

JLQCD (T. Kaneko) @ LATTICE 2017 Preliminary

  • Improved action
  • Both f+ and f0 over whole q2-range
  • Physical mass:
  • q2=0 through BCL z-expansion

Giorgio Salerno CHARM 2018

  • of DW fermions
  • D at rest frame
  • New ensembles: fjne lattice spacing

18/23

slide-20
SLIDE 20

Semileptonic decays - New Results

1/22 Giorgio Salerno LATTICE 2017 Giorgio Salerno CHARM 2018

JLQCD (T. Kaneko) @ LATTICE 2017 Preliminary

19/23

slide-21
SLIDE 21

Summary of results

1/22 Giorgio Salerno LATTICE 2017 Giorgio Salerno CHARM 2018

P r e l i m i n a r y

20/23

slide-22
SLIDE 22

Determinatjon of Vcd and Vcs

Giorgio Salerno CHARM 2018

Vcd(s) from semileptonic decays (errors dominated by theoretical inputs) Vcd(s) from leptonic decays (errors dominated by experimental inputs)

21/23

slide-23
SLIDE 23

CKM 2nd-row Unitarity

Giorgio Salerno CHARM 2018 22/23

slide-24
SLIDE 24

Conclusions & Outlooks

Giorgio Salerno CHARM 2018

✦ LQCD predictions of the decay constants of the D and Ds mesons

are very precise (errors below 1%, now ~0.2%). Uncertainties in CKM matrix elements dominated by experimental inputs LQCD simulations with very small lattice spacings and light see quarks at their physical masses are being performed

  • New determinations are required to confjrm systematic errors are

under control

  • No need (reduced) of chiral extrapolation better precision

Determinations of D(s) semileptonic form factors still need to be

  • improved. Uncertainties in CKM matrix elements dominated by

LQCD inputs

  • f+,0 over whole q2-range

✦ ✦

  • fT over whole q2-range

23/23

slide-25
SLIDE 25

Giorgio Salerno

Thank you for the attention

CHARM 2018

slide-26
SLIDE 26

CLS ensembles

Giorgio Salerno CHARM 2018

Other results

ETMC

  • B. Blossier, J. Heitger, M. Post
slide-27
SLIDE 27

Extractjon of the form factors

The two semileptonic form factors f 0 and f + can be determined from the matrix element of the vector current An alternative way to determine f 0 is to use the scalar density

Giorgio Salerno CHARM 2018

slide-28
SLIDE 28

To inject momenta we used non-periodic boundary conditions Both the D and the π(K) mesons can have non-zero momentum

Simulatjon Details

Giorgio Salerno CHARM 2018

slide-29
SLIDE 29

Lorentz Symmetry Breaking

corrected uncorrected

Giorgio Salerno

f0 vs. q2(GeV2)

CHARM 2018

slide-30
SLIDE 30

Results

Giorgio Salerno

In the continuum limit

CHARM 2018

slide-31
SLIDE 31

Determinatjon of Vcd and Vcs

Giorgio Salerno CHARM 2018

slide-32
SLIDE 32

3-points correlators

From 2-point correlators Form factors

Giorgio Salerno CHARM 2018

slide-33
SLIDE 33

Euclidean Correlators

Giorgio Salerno

Calculated on the lattice (Importance sampling Monte Carlo)

Statistical error

CHARM 2018

slide-34
SLIDE 34

Giorgio Salerno

Quenching

Gaussian integral for anticommutative (Grassmann) variables

det M encodes the contribution of see quark loops

CHARM 2018

slide-35
SLIDE 35

Modifjed z-expansion

Giorgio Salerno

and are parameters left free to move in the fit and have a polynomial dependence on

CHARM 2018

slide-36
SLIDE 36

f T(q2) at the physical point

ETMC – Tensor form factor

Giorgio Salerno CHARM 2018

ETMC