[PPT] - V ud Outlook : Experiment & Theory M.J. Ramsey-Musolf U Mass PowerPoint Presentation

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Vud Outlook : Experiment & Theory

CKM Workshop ACFI May 2019

M.J. Ramsey-Musolf

U Mass Amherst

http://www.physics.umass.edu/acfi/

My pronouns: he/him/his

Collaborators: All workshop participants

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Workshop Goals

Review recent theoretical developments

in the extraction of Vud and Vus from experimental measurements

Seek a consensus on the current values
f theoretical inputs and associated

theoretical uncertainties

Develop a roadmap for future, improved

theoretical evaluations and experimental tests

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Precision ~ BSM Mass Scale

Precision Goal:

δ ΔCKM ~ O(10-4)

Ultralight BSM Physics:

ΔCKM ~ ε2 ( α /4π )

ε < 1 (loop)

ΔCKM ~ C ( v/Λ )2

Heavy BSM Physics:

Λ ∼ 10 TeV (tree) Λ < 1 TeV (loop)

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Questions for This Discussion

How robust is the quoted uncertainty on the

new value of ΔR

V ?

What additional tests (theory, experiment) are

available ?

What is the roadmap to refined computation of

δNS ?

How important are contributions from other

region of the low-E nuclear response ? How to compute & how to test computations ?

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Dispersion Relations

γ W

0+(i) 0+(f) Radiative Correction: ⇤V A (0)

γW

= ↵ ⇡M

1

Z dQ2M 2

W

M 2

W + Q2 1

Z d⌫ (⌫ + 2q) ⌫(⌫ + q)2 F (0)

3

(⌫, Q2),

γ W ν

e

−

0+(i) 0+(f)

= 3↵ 2⇡ Z 1 dQ2M 2

W

Q2[M 2

W + Q2]M (0) 3 (1, Q2)

Relate F3

(0) and M3 (0) to data and/or

Compute F3

(0) and M3 (0) using same

methods used to describe semi- leptonic scattering processes with nucleon & nuclear targets

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Leptoproduction: Had & Nuc Response

Nuclei Free nucleons

Elastic

Discrete Levels

Quasi- Elastic

Hadronic Resonances Regge/ Deep Inelastic GDR

Elastic

Pion Production Hadronic Resonances Regge/ Deep Inelastic

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Recent Results: Single Nucleon

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Leptoproduction: Had & Nuc Response

Nuclei Free nucleons

Elastic

Discrete Levels

Quasi- Elastic

Hadronic Resonances Regge/ Deep Inelastic GDR

Elastic

Pion Production Hadronic Resonances Regge/ Deep Inelastic

Single nucleon: PRL 121 (2008) 241804

ΔR

V = 0.02361(38) 0.02467 (22)

“CMS” Preliminary

ΔR

V = 0.02361(38)

0.02433(32)

W. Marciano: this workshop

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Dispersion Relations

Compute contributions to M3

νp+νp at

each Q2 from different ω regions

Isospin rotate to M3

(0)

Refinements (WJM):
Implement 4 loop BjSR for

pQCD region

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Large NC Interpolator

Q0

2 = 1.08 GeV2

DR: C.-Y. Seng

Neutrino data ? # of resonances ? Marciano

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Recent Results: Nuclei

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Leptoproduction: Had & Nuc Response

Nuclei Free nucleons

Elastic

Discrete Levels

Quasi- Elastic

Hadronic Resonances Regge/ Deep Inelastic GDR

Elastic

Pion Production Hadronic Resonances Regge/ Deep Inelastic

Quasielastic response Part of δNS : “ CB

Nucl ”

New work

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Impact on δNS

Gorshteyn

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Implications: “Conventional Analysis”

Hardy

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Implications

final nucleus Hardy

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Implications

Hardy + New “CMS” ΔR ?

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Tests & Improvements: Single Nucleon

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Future Tests

Lattice computation of M3

(0) (Q2)

PV electron scattering

4F (0)

3

= F p

3,γZ − F n 3,γZ.

Isospin relation

SoLID ?
EIC ?
More neutrino data for M3

(0) (Q2)

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Lattice QCD & M3

(0) (Q2)

Feynman-Hellmann Theorem Seng

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Tests & Improvements: Nuclei

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Leptoproduction: Had & Nuc Response

Nuclei Free nucleons

Elastic

Discrete Levels

Quasi- Elastic

Hadronic Resonances Regge/ Deep Inelastic GDR

Elastic

Pion Production Hadronic Resonances Regge/ Deep Inelastic

Quasielastic response Part of δNS : “ CB

Nucl ”

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Impact on δNS

∆ δNS = α π ⇣ CQE − q(0)

S qACB

⌘ = −(4.6 ± 0.9) × 104

Optimistic:

Correlations
2-body currents
Rel corrections

Ave over 20 transitions Neglects A- dep variations

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QE Contribution: Refinements

Correlations
2-body currents
Rel corrections
Recent MIT group: 2N knockout

Apply state-of-art methods

ent-daughter
Consistency w/ CVC ?

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QE Contribution: Refinements

GFMC: 10B
Auxiliary Field MC: higher A

Quantum Monte Carlo LO β-Decay

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GFMC & AFMC

Pastore

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Other Nuclear Corrections

Nuclei Free nucleons

Elastic

Discrete Levels

Quasi- Elastic

Hadronic Resonances Regge/ Deep Inelastic GDR

Elastic

Pion Production Hadronic Resonances Regge/ Deep Inelastic

Low-lying transitions Part of δNS

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0+ ! 0+ Decay: δNS

One-body Two-body: GS ! GS Full nuclear Greens fn: excited intermediate states Towner 1992; T&H compilations Needed: state of art calc’s & tests w/ An

J. Engel

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Dispersion Corrections

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V V V γ γ V = γ

Beam normal asymmetry

V = Z0, W, γ

Abrahamyan et al, PRL 109 (2012) 192501

J Lab Hall A
Future: Mainz, J Lab

Two-boson exchange in semileptonic processes: important for elastic PV eN & eA scattering (12C) & nuclear β-decay; beam normal asymmetry, Olympus… provide tests

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0+ ! 0+ Dispersion Corrections: δNS

Towner & Hardy, PRC 91 (2015) 2, 025501

bF : scalar currents Input for Vud & CKM unitarity test

Re-compute with state-of-the-art many-body methods
Test w/ An predictions & expt for 10B, 14N, 26Mg, 34S, 38Ar, 42Ca, 46Ti, 50Cr, 54Fe
Investigate strategy for obtaining reduced error bars
e+ vs e- ?
Muons ?

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“Next Frontier” : Higher Order EW RC

µ− ν

e

˜ µ

−

W − ˜ χ

+

˜ χ

e

−

ν µ

Propagator Vertex & External leg

Cancel from Δrβ -Δrµ

Box

µ

−

ν µ ν

e

−

W

−

W

−

+! +

µ

−

ν µ ν

e

−

W

−

W

−

+

d u ν

e

W −

e

−

ν

e

W −

e

−

u d

ν

e

−

+!

d u

+!

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Other Issues

Ivanov: CPS + Wilkinson term Hayen: RC for GT decays

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