K. Long, April 18, 2023

Physics working group

– (not quite a) summary and plans

… with grateful thanks to PhysWG speakers and those whotook part in the discussions

Contents Introduction and motivation

The most difficult task (!)

What to assume about the machines

Impact

Muon physics

Work to do in preparation for first phys. grp. w/s Theoretical subgroup

Phenomenological subgroup

Experimental subgroup

Summary

Introduction The neutrino standard model?

Three active flavours Three, Dirac, mass eigenstates

Neutrino mass scale Mass hierarchy

MNS mixing matrix

Three mixing angles One CP phase

Physics beyond The Standard Model

100

0

0

c0

010

0

0

0

001

3

2

1

1212

1212

13-i

13

i1313

2323

2323

e

cs

sc

es

esc

cs

sc

Motivation: The masses are

so different, that must be a clue …

Neutrino mixing so different from quark mixing, that must be clue …

de Gouvea, Hernandez

Motivation: the era of sensitivity …

de Gouvea

Hernandez

NeutrinoFactory

Super-beam

O.M

ena (h

ep-p

h/0503097)

Motivation: … and precisionBurguet et al. (hep-ph/0503021)Beta-beam

050922 ISS Physics Meeting

Two main physics strategies

use of the high neutrino rate (>1020/year) and energy (10-50 GeV) of Neutrino Factory + LMD (“SuperMinos”)

detector of large but not huge mass (50-100 Kt), necessarily magnetic (a dense magnetized Iron detector, or, possibly, Li-Argon), a few 1000 Km away.

use of the lower neutrino rate (1018-19/year) and energy (sub-GeV) of Betabeam + “Megaton” low density detector of very large mass (0.5-1 Mt) and volume (0.5-1 Mm3) non magnetic (a Water Cerenkov detector, or possibly, again Li-Argon), a few 100 Km away (except for AGS).

νe + ν

νe

Nufact05

NNN05

Palladino

V. Palladino:Super Conventional Beams

R&D into machine (MERIT, MICE, …) essential

The most challenging task: 1

Incremental

Era ofsensitivity & precision

Optimum schedule Science driven Potential match to

funding window Challenge:

To make the case!

Era ofsensitivity & precision

The most challenging task: 2Incremental:

Implicationwait until13 known

To refute:Have to show that there exists a facility that gives significant improvement over all 13

Machine assumptions: Super-beam and Neutrino Factory

Kirk

4.520CNGS-400 GeV

7.5(17.5)

4.4

2.3

5.4

3.7

4.4

Neutrino

Peak Flux

At 2500km

109/GeV/m2/1MW

1.5BNL VLBL-28 GeV

18(40)Nufact-20(50) GeV

1.2T2K-50 GeV

10NuMi-120 GeV

1.0K2K-12 GeV

0.25SPL-2.2 GeV

Neutrino

Peak Energy

GeVBeam Energy

4.520CNGS-400 GeV

7.5(17.5)

4.4

2.3

5.4

3.7

4.4

Neutrino

Peak Flux

At 2500km

109/GeV/m2/1MW

1.5BNL VLBL-28 GeV

18(40)Nufact-20(50) GeV

1.2T2K-50 GeV

10NuMi-120 GeV

1.0K2K-12 GeV

0.25SPL-2.2 GeV

Neutrino

Peak Energy

GeVBeam Energy

only, one sign

Machine assumptions: Beta-beam, reference facility (100/100)

Benedict

M. Benedikt ISS CERN 11

Goals - Status

• For the base line design, the aims are (cf. Bouchez et al., NuFact’03):

– An annual rate of 2.9 1018 anti-neutrinos (6He) along one straight section– An annual rate of 1.1 1018 neutrinos (18Ne) at =100

always for a “normalized” year of 107 seconds.

• The present status is (after 8 months of the 4-year design study):

– Antineutrino rate (and 6He figures) have reached the design values but no safety margin is yet provided.

– Neutrino rate (and 18Ne figures) are one order of magnitude below the desired performance.

Machine assumptions: Green-field facility (350/350)

Lindroos/Hernandez

The case for a greenfield study: the higher the the better

• more signal: Ncc ~ x

• more significant energy dependence: intrinsic degeneracy• more significant matter effects: hierarchy

Bring the -beam to the forefrontand find out the machine neededto achieve:

NL(km) p

10 18-1019~700< 350

NL(km) p

10 18-1019~700< 350

E.g. Refurbished SPS Eg. CERN-Canfranc ?

Burguet-Castell,Casper, Gomez-Cadenas, P.H. Sanchez

Impact: Large scale structure: Kachelreiss

Power-density of CMB has significant implications for neutrino mass

Challengesof neutrinophysics:King

Neutrino Physics: Challenges

Seven challenges f or neutrino physics:

#1. Count the number of neutrinos

#2. Measure the neutrino mass scale

#3. Determine the sign of the mass ordering

#4. Measure the deviation of 23 f rom maximal

#5. Measure 13

#6. Measure

#7. Measure the deviation of 12 f rom tri-bimaximal mixing

Impact: … models Tri-bimaximal mixing:

Hypothesis: Motivated by ‘symmetry’

Models: Links quarks and leptons

Consistent with tri-bimaximal mixing

12 23 13

12 23

35.26 , 45 , 0

1 1sin , sin

3 2

Harrison, Perkins, Scott

But expect deviations f rom tri-bimaximal mixing in realistic models

SFK hep-ph/ 0506297

N.B. deviation depends on which is thereby predicted in terms of 12

Constraint!

King

04/18/23

The Muon Trio:• Lepton Flavor Violation

• Muon MDM (g-2) chiral changing

• Muon EDM

Lee Roberts Ellis

04/18/23

General Statements

• We know that oscillate– neutral lepton flavor violation

• Expect Charged lepton flavor violation at some level– enhanced if there is new dynamics at the

TeV scale• in particular if there is SUSY

• We expect CP in the lepton sector (EDMs as well as oscillations)– possible connection with cosmology

(leptogenesis)

04/18/23

At a -factory, also have a -factory

• This flux will permit:– A dedicated search for a permanent

muon EDM ( P, T ) to 10-24 e cm and beyond.

– Search for muon Flavor Violation to below 10-18 to 10-19 level, or if FV is observed, it will be possible to make detailed studies of the reaction

First steps towards physics chapter1. Physics and phenomenology

1.1 Context

Themes in today’s particle physics:

Origin of mass: Higgs & Tevatron, LHC, ILC

Origin of flavour:

– In quark sector: Babar, Belle, Tevatron, LHC, ILC, …

– In lepton sector: <list of neutrino and muon experiments>, future experiments …

Search for new physics, SUSY etc: Tevatron, LHC, ILC, CLIC, rare decays (muon, kaon, etc.)

Goal is to show importance of developing future neutrino programme in terms of an overall vision of the field.

1.2 Review and overview

1.2.1 The standard scenario

3-flavour mixing: issue is to define terminology. Need to include absolute mass scale, and Majorana/Dirac nature.

Need to note absence of charged lepton mixing in the standard scenario. Reason is to carry through muon case.

1.2.2 Alternative hypotheses

Neutrinos:

Non-standard phenomenology: e.g. more than three neutrino species. Note that it is expected that MiniBOONE will have produced a result by the end of the study.

Models: SUSY etc. Reason is to show that there are underlying mechanisms that precision measurements of neutrino oscillation can probe. Need to lay the foundations for consideration of the precision that is required to probe the various models and the analysis of the precision which can be achieved in the various facilities.

Muons:

Non-standard phenomenology: physics of searches for lepton flavour violation (LFV) and a permanent electric dipole moment (EDM).

1.2.3 Impact

Study of properties of neutrinos, and muon properties and decays beyond the standard model, impacts many fields beyond ‘just’ neutrino physics. So, review impact of these measurements on:

Cosmology: e.g. leptogenesis. Complementarity with cosmological constraints on absolute neutrino mass scale. large-scale structure.

Astrophysics: e.g.

Dark matter constraints from the muon sector.

1.2.4 Definition of context

Neutrinos:

Present knowledge;

Likely development over next 5, 7, 10 years, i.e. set context in which next generation facility will operate;

Define remit: i.e. review the measurements that are required beyond planned experiments, i.e. in the ‘precision era’. This means , 13 of course, but indicate need for unitarity tests flexibility etc.

Muons:

Present knowledge

Likely developments in dipole moments and lepton LFV in near term: muon (g-2), MEG (the μ→eγ experiment at PSI).

Review the physics of the measurements which can only be done at a very intense muon source (HIMS), such as a search for a muon EDM, and detailed LFV studies if it’s found at PSI, or more sensitive μ → e conversion experiments and muonium to antimuonium conversion at the HIMS if LFV is not found at PSI.

1.3 Specification

Neutrinos:

For the moment, take the goal to be to get an understanding of the neutrino at least as good as that which we presently have of quarks. Would like to review the precision required, in the precision era not only on and 13 but also on the unitarity constraints.

In particular, need to define:

Assumptions on accelerator performance – for super-beam, beta-beam and NF;

Assumptions on detector performance – for the options considered by detector group;

Definition of baseline tools used for analyses: e.g. Nuance/Globes. Need to discuss early if propose to standardise.

Neutrino cross sections: status and what will be assumed. Through systematic error analysis in section 1.4 will feedback into the needer R&D programme.

This means an initial request for a set of working assumptions and a ‘review loop’ by which the final set of assumptions is defined.

Muons:

Take the sensitivity goal for LFV to equal or exceed the PRIME LOI (at J-PARC) single event sensitivity of 10-18.

Take the sensitivity goal for a search for a permanent muon EDM to be at least 10-24 e cm, with a clear path for upgrading this sensitivity by one to two orders of magnitude.

1.4 Performance

Neutrinos:

Need to present results in a ‘coherent’ way, i.e. building on the definitions from 1.1.1 need to assess performance in terms of the same variables for each option, of course using the assumptions from 1.2. For now I have separated the assessment of performance from the comparison. The performance would have to be presented for each of super-beam, beta-beam and Neutrino Factory so would end up with a series of sub-sections. Would need to consider sensitivity to , 13, precision on standard parameter sets (for unitarity tests for example) as well as measurements that would have sensitivity to the various non-standard scenarios.

Need to include analysis of how to remove degeneracies and ambiguities. Would also need to compress information into a sensitivity chart to allow an accessible summary to be made.

1.4.1 Super-beam

1.4.2 Beta-beam

1.4.3 Neutrino Factory

Muons:

Need to assess physics performance of muon facility. Perhaps as a function of assumptions from 1.2.

Study of sensitivity to systematic errors, including backgrounds for the LFV experiments and other systematic errors for the EDM experiment.

1.5 Comparisons & combinations

Crucial contribution: based on specifications for measurements and performance assumptions from 1.2 need to make a critical comparison of the various facilities.

Physics performance as a function of energy, here or in 1.4?;

Physics gain at NF from more than one far detector;

Role of NF if 13 is large;

Is NF ‘better’ than combination of other facilities, in principle – and could NF come earlier than the set of facilities that are required to do as well or better;

Impact of lack of knowledge on neutrino cross sections on measurements from the various facilities.

Phyiscs gain and symbiosis of a muon facility and muon program at the NF.

Need to present the method by which the facilities were combined, and the assumptions made. Again, need to compress the combined results into a sensitivity chart to allow succinct presentation of the results. Analysis must include removal of degeneracies.

1.6 Conclusions and plans

Conclusions and recommendations, plus the list of future work.

Physics working group workshop #1

14th to 21st November 2005

Department of Physics, Blackett Laboratory, Imperial College London,

Exhibition Road, London, SW7 2AZ

First bulletin

1. General Information The objectives of the Physics working group of the international scoping study of a future Neutrino Factory and super-beam facility (ISS) are:

To review the theoretical descriptions of the neutrino, devise measurements by which the various models can be distinguished, and to assess the impact of measurements of neutrino oscillations on particle physics, astrophysics and cosmology;

To review the standard three-neutrino mixing formalism and to evaluate the degree to which the super-beam, beta-beam, and Neutrino Factory, alone or in combination, can distinguish between the various models of neutrino mixing and determine optimum parameter sets for these investigations;

To make realistic estimates of the performance of the super-beam, beta-beam, and Neutrino Factory, alone or in combination.

To review the theoretical description of the non-standard model contributions to the muon electric and magnetic dipole moments, as well as to muon processes which violate lepton flavour.

To make realistic estimates of the sensitivity to this physics which could be obtained at a high intensity muon facility at a neutrino factory.

Propose: Series of w/ss

to focus work and to share tools and ideas

Each w/s documents progress and identifies next steps

Need to specify goals for first workshop This week!

• Plan to run as a ‘drop in centre’:

• Recognises that not all cancome for all the days … though great if you can

• Weekend included for those that it helps with travel

• Working meeting – emphasis on discussion and WORK!

• Specific goals now defined!

• WWW page to be updated

Common tools: Enhance efficiency of those new to

calculating sensitivities to oscillation parameters

Huber

Theoretical subgroup: Main task:

What is scientific gain of precision measurements of neutrino properties?

Origin of universe … c.f. Origin of mass for LHC Super-symmetry – the last space-time symmetry – for ILC

Neutrino mass Argument presented by Pilar

Job in preparation for w/s #1: Test to see if ‘origin of universe’ argument could

be developed Steve King (with KL as naïve follower)

Development of mass-scale arguments Andre de Gouvea

23/04/18

Sensitivity to unitarity and physics beyond SM

Standard scenario assumes three flavors and vanishing off-diagonal elements of the matter term:

scenario 1: existence of sterile neutrinos

scenario 2: existence of flavor changing int.

000

000

00A

3E00

02

E0

001

E1-UU

Possible source of violation of unitarity:

Phenomenological subgroup Yasuda

Precision requiredto test scenarios?

Pheno/Experimental subgroup Calculate sensitivity in 13 - plane:

Two reference superbeams SPL, T2K, NOvA Obtain BNL info for w/s

Two reference beta-beams (100/100), (350/350) Baselines: 130, 700

Two reference neutrino factories (20, 50) – assume store both charges Baselines

Define reference 1000, 3000 … but hope that some optimisation can be done

AEDL for options to be posted on WWW Action: Patrick Huber/KL Comparison of results:

From GLOBES: Patrick Huber, Paul Harrison (et al) From ‘Valencia code’: Pilar Hernandez (et al) From ‘Madrid code’: Stefano Rigolin (et al.)

What: Perform fits for small number of assumed parameter sets Comment on discrete degeneracies

Goal is to establish a baseline for development of comparison of facilities alone and in combination

Need i/p from detector group … detector performance assumptions: Suggest:

Iron Cal: MINOS + high granularity - for NF for 14Nov LAr? H2O Ç – for sb and low gamma beta beam for 14Nov Scint – for high gamma beta beam for 14Nov Emmulsion

A challenging programme …

… but at least we’ll have started!