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BSM and beta decay Vincenzo Cirigliano Los Alamos National - - PowerPoint PPT Presentation

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ACFI Workshop on Beta decays as a probe of new physics Amherst, Nov 1-3 2018 BSM and beta decay Vincenzo Cirigliano Los Alamos National Laboratory Outline New physics in beta decays: generalities and EFT framework Constraints on

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BSM and beta decay

Vincenzo Cirigliano Los Alamos National Laboratory

ACFI Workshop on “Beta decays as a probe of new physics” Amherst, Nov 1-3 2018

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  • New physics in beta decays: generalities and EFT framework
  • Constraints on non-standard charged current interactions
  • global analysis of beta decays
  • collider input: LEP

, LHC

  • comparison of sensitivities
  • Summary and outlook

Outline

Special thanks to Martin Gonzalez-Alonso for sharing his slides from the WE-Heraeus-Seminar on “Particle Physics with Cold and UltraCold Neutrons” October 24-26, 2018, Bad Honnef

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Semileptonic processes: SM and beyond

  • In the SM, W exchange ⇒

V-A currents, universality

1/Λ2 GF ~ g2Vij/Mw2 ~1/v2

,τ

WR, H+, leptoquarks, Z’, SUSY,…

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Semileptonic processes: SM and beyond

  • In the SM, W exchange ⇒

V-A currents, universality

1/Λ2 GF ~ g2Vij/Mw2 ~1/v2

,τ

WR, H+, leptoquarks, Z’, SUSY,…

  • Broad sensitivity to BSM scenarios
  • Experimental and theoretical precision at or approaching 0.1% level

Probe effective scale Λ in the 5-10 TeV range

SUSY analyses: Bauman, Erler, Ramsey-Musolf, arXiv:1204.0035, … Kurylov & Ramsey-Musolf hep-ph/0109222. … Hagiwara et al1995 … Barbieri et al 1985 …

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Connecting scales — EFT

To connect UV physics to neutron and nuclear beta decays, use EFT

Matching to BSM scenarios Perturbative matching within SM

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Connecting scales — EFT

To connect UV physics to neutron and nuclear beta decays, use EFT

Matching to BSM scenarios Perturbative matching within SM Hadronic matrix elements Nuclear matrix elements Non-perturbative strong interactions

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  • New physics effects are encoded in ten quark-level couplings

Effective Lagrangian at E~GeV

  • Quark-level version of Lee-Yang effective Lagrangian, allows us

to connect nuclear & high energy probes

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  • New physics effects are encoded in ten quark-level couplings

Effective Lagrangian at E~GeV

Can interfere with SM: linear sensitivity to εi

Bhattacharya et al., 1110.6448 VC, Graesser, Gonzalez-Alonso 1210.4553

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  • New physics effects are encoded in ten quark-level couplings

Effective Lagrangian at E~GeV

Interference with SM suppressed by mν/E: quadratic sensitivity to εi ~ Can interfere with SM: linear sensitivity to εi

Bhattacharya et al., 1110.6448 VC, Graesser, Gonzalez-Alonso 1210.4553

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  • Work to first order in rad. corr. and new physics

Effective Lagrangian at E~GeV

Fermi constant extracted fro muon lifetime, possibly “contaminated” by new physics

Marciano-Sirlin 1981 Sirlin 1982

SM rad. corr. ⊃ “large log” (α/π)×Log(MZ/μ) Note: besides the pre-factor, ϵR appears in nuclear decays in the combination gA ≡ gA × (1- 2ϵR) _

Bhattacharya et al., 1110.6448 VC, Graesser, Gonzalez-Alonso 1210.4553

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  • 1. Differential decay distribution

Lee-Yang, 1956 Jackson-Treiman-Wyld 1957

Theory input: gV,A,S,T (from lattice QCD) + rad. corr. a(gA), A(gA) , B(gA, gαεα), … isolated via suitable experimental asymmetries

How do we probe the εα? (1)

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Nucleon charges from lattice QCD

With estimates of all systematic errors (mq, a, V, excited states)

Bhattacharya et al. 1806.09006

gS ~10% gT ~5% gA 1%

Chang et al. (CalLat) 1805.12030

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  • 2. Total decay rates

How do we probe the εα? (2)

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  • 2. Total decay rates

Experimental input

Lifetimes, BRs Q-values → phase space

How do we probe the εα? (2)

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  • 2. Total decay rates

Theory input

Hadronic / nuclear matrix elements and radiative corrections Lattice QCD, chiral EFT, dispersion relations, …

How do we probe the εα? (2)

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  • 2. Total decay rates

Channel-dependent effective CKM element

~

How do we probe the εα? (2)

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  • 2. Total decay rates

For nuclei, rate traditionally written in terms of “corrected FT values” Nucleus-dependent radiative & Isospin Breaking correction “Inner” radiative correction ΔR

V= (2.36 ± 0.04)%

[Marciano-Sirlin 2006]

How do we probe the εα? (2)

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  • 2. Total decay rates

For nuclei, rate traditionally written in terms of “corrected FT values” Nucleus-dependent radiative & Isospin Breaking correction “Inner” radiative correction ΔR

V= (2.467 ± 0.022)%

[Seng et al. 1807.10197]

How do we probe the εα? (2)

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Snapshot of the field

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732 & M. Gonzalez-Alonso slides

  • Experimental precision between ~0.01% and few %

Nuclei

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Snapshot of the field

  • Experimental precision between ~0.01% and few %

“Corrected” FT values FT values before including nucleus-dependent radiative correction

Hardy-Towner 1411.5987

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732 & M. Gonzalez-Alonso slides

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Snapshot of the field

  • Experimental precision between ~0.01% and few %

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732 & M. Gonzalez-Alonso slides

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Results of global fit to low-E data

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732

  • Standard Model fit (λ= gA/gV)
  • Fit driven by Ft’s (0+ →0+)

and τn (not An)

λ Vud (1+ ΔR)1/2 Experimental Radiative corrections (ΔR)

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Results of global fit to low-E data

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732

  • Standard Model fit (λ= gA/gV)
  • Fit driven by Ft’s (0+ →0+)

and τn (not An)

λ Vud (1+ ΔR)1/2 Experimental New Radiative corrections (ΔR) [Seng et al. 1807.10197]

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Results of global fit to low-E data

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732

  • Fit including BSM couplings (driven by Ft’s (0+ →0+) , τn, and An)

1st error: experimental 2nd error: ΔR, gA , gS , and gT ~2 % → ~ 0.5% ** ~0.2 % ~0.1 %

** CalLat 1805.12030

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Cabibbo universality test

Extraction dominated by 0+→0+ nuclear transitions Extraction dominated by K decays: K→πeν & K→μν vs π→μν (Vus/Vud)

Hardy-Towner 1411.5987 CKM 2016 FLAVIANET report 1005.2323 and refs therein Lattice QCD input from FLAG 1607.00299 and refs therein + MILC 2018 1809.02827

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Vus from K→ μν Vus from K→ πlν

ΔCKM = - (4 ± 5)∗10-4 ~ 1σ ΔCKM = - (12 ± 6)∗10-4 ~ 2σ

K→ μν K→ πlν unitarity 0+ → 0+ 0.4% 0.02%

Cabibbo universality test

Vus _ Vud _

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SLIDE 27

Vus from K→ μν Vus from K→ πlν

ΔCKM = - (4 ± 5)∗10-4 ~ 1σ ΔCKM = - (12 ± 6)∗10-4 ~ 2σ

Hint of something [ε’s ≠0] or SM theory input? Worth a closer look: at the level of the best LEP EW precision tests, probing scale Λ~10 TeV

K→ μν K→ πlν unitarity 0+ → 0+ 0.4% 0.02%

Cabibbo universality test

Vus _ Vud _

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Vus from K→ μν Vus from K→ πlν

ΔCKM = - (14 ± 4)∗10-4 ~3.5σ ΔCKM = - (22 ± 5)∗10-4 ~4.5σ

With new radiative corrections

[Seng et al. 1807.10197] K→ μν K→ πlν unitarity 0+ → 0+ 0.4% 0.02%

Cabibbo universality test

Vus _ Vud _

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Impact of neutrons

  • Independent extraction of

Vud @ 0.02% requires:

δτn ~ 0.35 s δτn/τn ~ 0.04 % δgA/gA ~0.15% → 0.03% (δa/a , δA/A ~ 0.14%) UCNτ @ LANL [τn~ 877.7(7)(3)s] is almost there, will reach δτn ~ 0.2 s δA/A < 0.2% can be reached by PERC, UCNA+ δa/a ~ 0.1% at Nab

1707.01817

Czarnecki, Marciano, Sirlin 1802.01804

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VC, Gonzalez-Alonso, Jenkins 0908.1754

Interplay with High Energy physics

  • Need to know high-scale origin of the various εα

Match SM-EFT and SM-EFT’

  • Model-independent statements possible in “heavy BSM” scenarios:

MBSM > TeV → new physics looks point-like at collider

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SLIDE 31

VC, Gonzalez-Alonso, Jenkins 0908.1754

Interplay with High Energy physics

Gauge invariance

dj ui

  • Need to know high-scale origin of the various εα

εL,R originate from SU(2)xU(1) invariant vertex corrections E.g. from WL-WR mixing in Left-Right symmetric models

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VC, Gonzalez-Alonso, Jenkins 0908.1754

Interplay with High Energy physics

…

dj ui

  • Need to know high-scale origin of the various εα

εL,R originate from SU(2)xU(1) invariant vertex corrections dj ui εS,P

,T and one contribution to

εL arise from SU(2)xU(1) invariant 4-fermion operators

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SLIDE 33

dj ui

  • Need to know high-scale origin of the various εα

Interplay with High Energy physics

εL,R originate from SU(2)xU(1) invariant vertex corrections dj ui

  • LEP:
  • Strong constraints (<0.1%) on L-handed vertex corrections (Z-pole)
  • Weaker constraints on 4-fermion interactions (σhad)

εS,P

,T and one contribution to

εL arise from SU(2)xU(1) invariant 4-fermion operators

  • What about LHC?
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  • The effective couplings εα contribute

to the process pp → eν + X

  • No excess

events in transverse mass distribution: bounds on εα

mT(GeV) mT(GeV)

LHC sensitivity: 4-fermions

Bhattacharya et al., 1110.6448, VC, Graesser, Gonzalez-Alonso 1210.4553

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LHC sensitivity: vertex corrections

  • Vertex corrections inducing εL,R in the SM-

EFT involve the Higgs field (due to SU(2) gauge invariance)

  • Can be probed at the LHC by associated Higgs + W production

εL,R εL,R

H W W q q’

  • S. Alioli, VC, W. Dekens, J. de Vries, E. Mereghetti 1703.04751

εL εR

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  • S. Alioli, VC, W. Dekens, J. de Vries, E. Mereghetti 1703.04751

Z pole

Example 1: εL and εR couplings

ΔCKM ∝ εL+εR δΓ(π→μν) ∝ εL − εR [fπ from LQCD] Constraint on εR uses gA =1.271(13) (CalLat 1805.12030) Neutron decay: λ = gA (1 − 2 εR) Z-pole → εL(v) Falkowski et al 1706.03783 Z pole

(Run 2 projection)

εL εR

90%CL, assumes only two operators at high scale

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  • S. Alioli, VC, W. Dekens, J. de Vries, E. Mereghetti 1703.04751

Z pole

Example 1: εL and εR couplings

ΔCKM ∝ εL+εR δΓ(π→μν) ∝ εL − εR [fπ from LQCD] Constraint on εR uses gA =1.271(13) (CalLat 1805.12030) Neutron decay: λ = gA (1 − 2 εR) Z-pole → εL(v) Falkowski et al 1706.03783 Z pole

(Run 2 projection)

εL εR

90%CL, assumes only two operators at high scale

Several lessons:

  • Beta decays can be quite competitive with collider
  • Connection between CC and NC (gauge invariance!)
  • Caveat: going beyond a 2-operator analysis relaxes some of these

constraints (but not the one on εR from λ)

  • All in all, beta decays provide independent competitive constraints in a

global analysis

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Example 2: εS and εT couplings

εS,T @ μ= 2 GeV (MS-bar)

CURRENT

εS,T @ μ= 2 GeV (MS-bar) LHC 36fb-1 @ 13 TeV

Bhattacharya et al 1806.09006

gS =1.01(10) gT =0.99(4)

Bhattacharya et al (PNDME) 1806.09006 Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732

Current low-E data: dominated by 0+→ 0+, τ(n), A(n)

  • 1.0×10-3 < gS εS < 3.2×10-3

0+ →0+ (bF)

Towner-Hardyl, 2010

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Example 2: εS and εT couplings

εS,T @ μ= 2 GeV (MS-bar)

FUTURE

b (n) @ 0.001 b (6He) @ 0.001 LHC puts very strong constraints

  • n 4-fermion

interactions Prospective beta decay measurements competitive, probing ΛS,T ~ 5-10 TeV gS =1.01(10) gT =0.99(4)

Bhattacharya et al (PNDME) 1806.09006

LHC 36fb-1 @ 13 TeV

Bhattacharya et al 1806.09006 Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732

Current low-E data: dominated by 0+→ 0+, τ(n), A(n)

  • 1.0×10-3 < gS εS < 3.2×10-3

0+ →0+ (bF)

Towner-Hardyl, 2010

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Beta decays in specific models

  • Qualitative picture:

WR H+

u e d ν LQ

“DNA matrix”

...

YOUR FAVORITE MODEL

...

Can be made quantitative, including LHC constraints on each model

  • Beta decays can play very useful diagnosing role
  • Model → set overall size and pattern of effective couplings
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Summary

  • β decays with sufficient th. and expt. precision (< 0.1%) remain a

very competitive probe of new physics

  • Discovery potential depends on the underlying model. However,

for heavy mediators, EFT shows that a discovery window exists well into the LHC era (simple examples: εL-εR and εS-εT plots)

  • Beta decays play unique role in probing vertex corrections εL-εR

(not enough precision at the LHC)

  • Beta decays can be competitive probes of scalar and tensor

interactions if precision reaches < 0.1%

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  • The next frontier in beta decays will likely include
  • Experiment:
  • δτn ~ 0.1s
  • <0.1% precision in decay correlation coefficients
  • Theory:
  • gA at sub-percent level from LQCD
  • Radiative corrections: improved data for

dispersive method and lattice QCD analysis

Outlook

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Backup

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Summary table

  • This table

summarizes a large number of measurements and th. input

  • Already quite

impressive. Effective scales in the range Λ= 1-10 TeV (ΛSM ≈ 0.2 TeV)

VC, S.Gardner, B.Holstein 1303.6953 Gonzalez-Alonso & Naviliat-Cuncic 1304.1759

Gonzalez-Alonso, Naviliat-Cuncic, Severijns, 1803.08732

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  • Helicity suppressed in the SM (V-A)

π-

  • Predicted very precisely in the SM (0.01%): Rπ = 1.2352(1) ×10-4
  • Experiment: Rπ = 1.2300(40) ×10-4 will go down to 0.05% level
  • This ratio probes a whole set of εP couplings (ν flavor not observed)

Marciano-Sirlin 93 VC-Rosell ’07 TRIUMF and PSI

α=e, μ β=e,μ,τ

Rπ = Γ(π→eν[γ] )/Γ(π→μν[γ])

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  • Neglecting non-enhanced εL-εR terms:
  • No constraint if
  • Assume all εP of similar size

(neglect me/mμ)

  • Allowed region is an annulus
  • f thickness 1.38 ×10-6
  • Marginalize wrt εPex

me/B0

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SLIDE 47
  • Constraint on εS,T via EW radiative corrections: P operator,

generated at high scale Λ, induces S and T operators at low scale μ

P S,T

∝

  • With log(Λ/μ) ~10, |εS| < 8 ×10-2 and |εT| < 10-3

Voloshin ’92 Campbell-Maybury ’05 Herczeg 95

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Standard Model analysis

  • εα=0 and take

Vud from 0+ → 0+:

  • UCN lifetime and post-2002 gA

consistent with SM (blue line) ⇒

  • “favored values” within the SM
  • if confirmed, will put tightest

constraints on BSM interactions

Trap Post 2002 Pre 2002 Beam

Czarnecki, Marciano, Sirlin 1802.01804 42

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Standard Model analysis

  • εα=0 and take

Vud from 0+ → 0+:

Czarnecki, Marciano, Sirlin 1802.01804 43

1.255 1.260 1.265 1.270 1.275 1.280 1.285 870 875 880 885 890 895

Impact of ϵR = 0.003 Trap Post 2002 Pre 2002 Beam

  • UCN lifetime and post-2002 gA

consistent with SM (blue line) ⇒

  • “favored values” within the SM
  • if confirmed, will put tightest

constraints on BSM interactions

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SLIDE 50

Status of scalar and tensor charges

Martin Gonzalez-Alonso

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  • Vud from 0+→ 0+ nuclear β decays

Nucleus-dependent

  • rad. corr.

(Z, Emax ,nuclear structure)

Sirlin-Zucchini ‘86 Jaus-Rasche ‘87

Coulomb distortion

  • f wave-functions

Towner-Hardy Ormand-Brown

Ab initio methods?

Vud from 0+ → 0+ nuclear decays

Nucleus-independent short distance rad. corr.

Marciano-Sirlin ‘06

Further improvements with dispersion relations, Lattice QCD?

ΔR =2.36(4)%

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Z of daughter nucleus Z of daughter nucleus

Vud = 0.97417 (21)

  • Vud from 0+→ 0+ nuclear β decays

Vud from 0+ → 0+ nuclear decays

Hardy-Towner 1411.5987

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K→ μν vs π→ μν K→ πlν

Vus from K decays

@ 0.25% @ 0.34%

  • Lattice QCD calculations (summaries from FLAG 2016)
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K→ πlν

Vus from K decays

  • Lattice QCD calculations

mπ → mπphys, a → 0, dynamical charm

FK/Fπ = 1.1960(25) [stable] Vus / Vud = 0.2313(7) f+K→π(0)= 0.959(5) → 0.970(3) Vus = 0.2254(13) → 0.2231(9)

FLAG 2016 1607.00299 and refs therein

  • Radiative corrections computed to O(e2p2) in ChPT
  • World data: FLAVIANET report 1005.2323 and refs therein

K→ μν vs π→ μν

VC, H. Neufeld 1107.6001 VC, M. Giannotti, H. Neufeld 0807.4507