Accelerator-based Lecture 1

Kendall Mahn

26/08/2015, INSS K.Mahn, Acc-nu sources 1 sources The Sun (fusion) Galacc and Our atmosphere extra-galacc sources (e.g SN)

Radioacve Accelerators decays

Reactors

26/08/2015, INSS K.Mahn, Acc-nu sources 2 Neutrino sources The Sun (fusion) Galacc and Our atmosphere extra-galacc sources (e.g SN)

At , mean free path through lead is 1 light year

Making precision neutrino measurements require enormous detectors and intense sources

Radioacve Accelerator-driven neutrino beams are one such method Accelerators decays

Reactors

26/08/2015, INSS K.Mahn, Acc-nu sources 3 of accelerator based ν experiments

Neutrino oscillaon • Measurements of neutrino mixing parameters • Nonstandard neutrino mixing

Electroweak tests • Lorentz violaon 2 • Measurement of sin θW • Discovery of νµ, ντ

Neutrino interacons • Charged current interacons • interacons • Deep inelasc scaering • Structure funcons

Detector R&D

26/08/2015, INSS K.Mahn, Acc-nu sources 4 Physics of accelerator based ν experiments

Neutrino oscillaon K2K, MINOS, T2K, NOvA • Measurements of neutrino mixing parameters OPERA (& ICARUS) • Nonstandard neutrino mixing LSND, Karmen, MiniBooNE, MicroBooNE CHORUS, NOMAD Electroweak tests • Lorentz violaon CCFR, CDHS, NuTeV 2 • Measurement of sin θW , DONUT • Discovery of νµ, ντ CHARM

Neutrino interacons • Charged current interacons ANL, BNL • Neutral current interacons experiments • Deep inelasc scaering SciBooNE, MINERvA • Structure funcons COHERENT, CONNIE

Detector R&D

Incomplete list of experiments; later lectures will ArgoNeuT cover future and proposed experiments PEANUT Most experiments cover mulple physics topics

26/08/2015, INSS K.Mahn, Acc-nu sources 5 Physics of accelerator based ν experiments

Neutrino oscillaon K2K, MINOS, T2K, NOvA • Measurements of neutrino mixing parameters OPERA (& ICARUS) • Nonstandard neutrino mixing LSND, Karmen, MiniBooNE, MicroBooNE Focus for this set of talks CHORUS, NOMAD Electroweak tests • Lorentz violaon CCFR, CDHS, NuTeV 2 • Measurement of sin θW Gargamelle, DONUT • Discovery of νµ, ντ CHARM

Neutrino interacons Neutrino cross secons covered by K. McFarland • Charged current interacons ANL, BNL bubble chamber • Neutral current interacons experiments • Deep inelasc scaering SciBooNE, MINERvA • Structure funcons COHERENT, CONNIE

Detector R&D Neutrino detecon techniques covered by K. Scholberg ArgoNeuT PEANUT

26/08/2015, INSS K.Mahn, Acc-nu sources 6 Open quesons about neutrino mixing Open questions in neutrino mixing

# νe & #Ue1 Ue2 Ue3 & # ν1 & Flavor eigenstates % ( % ( % ( Mass eigenstates (coupling to the W) νµ = Uµ1 Uµ2 Uµ 3 ν2 (definite mass) % ( % ( % ( $ ντ ' $Uτ1 Uτ 2 Uτ 3 ' $ν3 ' Unitary PMNS mixing matrix

Three observed flavors of neutrinos (νe, νµ , ντ) means U is represented by three independent mixing angles (θ , θ , θ ) and a CP-violang phase δ 12 23 13 Measurements by accelerator-based experiments

Is θ23 mixing maximal (θ23=46°±3°)

Is there CP violaon (non- PDG2014 PDG2014 zero δ?)

26/08/2015, INSS K.Mahn, Acc-nu sources 7 Open quesons about neutrino mixing Open questions in neutrino mixing

3

2 Δm 32 > 0 2 2 2 Δmij = mi − m j 2 2 Δm 21 1

2 Neutrino mass squared (m€ i ) Neutrino oscillaon measurements are sensive to the interference of the mass eigenstates (Δm2)

Two observed mass “splings”, determined from atmospheric/accelerator and solar/reactor neutrino experiments, respecvely 2 2 -3 2 § Δm (atmospheric) = |Δm 32|~ 2.4 x 10 eV 2 2 -5 2 § Δm (solar) = Δm 21 ~ 7.6 x 10 eV

26/08/2015, INSS K.Mahn, Acc-nu sources 8 Open quesons about neutrino mixing Open questions in neutrino mixing

3 2 2 Δm 21 2 Δm 32 > 0 1

m2 2 Δ 32 < 0 2 Δm 21 1 3

2 Neutrino mass squared (mi )

2 The sign of Δm 32, or the “mass hierarchy” is sll unknown 2 § Normal “hierarchy” is like quarks (m1 is lightest, Δm 32 >0 ) 2 § Inverted hierarchy has m3 lightest (Δm 32 <0)

What is the mass hierarchy?

26/08/2015, INSS K.Mahn, Acc-nu sources 9 Oscillaon probabilies Oscillation probabilities

2 2 |Δm 32| >> Δm 21, producing high frequency and low frequency oscillaon terms

( 1.27Δm2 L + ( 2.54Δm2 L+ P 4 Re U U * U * U sin2 ij 2 Im U U * U * U sin ij αβ = δαβ − ∑ [ βi αi βj αj ] * - + ∑ [ βi αi βj αj ] * - i> j ) E , i> j ) E ,

2 2 2 If choose L, E, such that sin (Δm 32L/E) is of order 1, then Δm 21 terms will be € small. Then... ν “disappear’’ into ν , ν µ e τ ( 1.27 m2 L + 2 2 Δ 32 P(νµ → ν µ ) ≅ 1− sin 2θ23 sin * - ) E ,

A small amount of νe will “appear’’ 2 2 Δm 31 ~ Δm 32 € 2 2 2 2 ' 1.27Δm31L * P(νµ → νe ) ≅ sin 2θ13 sin θ23 sin ) , ( E + Only leading order terms shown

26/08/2015, INSS K.Mahn, Acc-nu sources 10 € Accelerator-basedAccelerator based neutrino neutrino sources sources

95m Decay region Neutrino beam π+

30 GeV Carbon 3 Magnec and Beam beam Target focusing decay to neutrinos dump ``horns”

To measure νµ disappearance, and νe appearance requires a νµ source* § Atmospheric neutrinos include both νe and νµ from producon § Accelerator based beams are pure νµ from a proton -> meson -> decay chain: § Typically >99.9% νµ § Producon of neutrinos is “known”, scalable with accelerator improvements § Also possible to create anneutrino source

*There are other ways to probe oscillaon physics with intense sources, more later

26/08/2015, INSS K.Mahn, Acc-nu sources 11 Oscillaon probabilies Oscillation probabilities

νµ to νe appearance probability expansion:

E A =2 2G N F e m2 32

Key players: 2 -3 2 § |Δm 32|~ 2.4 x 10 eV (atmospheric mass spling) § Mixing angles: θ12, θ23, θ13 Approximaon from § CP-violang phase δCP M. Freund, PRD 64, 053003

Neutrinos vs. anneutrinos probability depends on δCP, mass hierarchy (sign 2 of Δm 32 ) • Mass hierarchy is determined through dependence of νe, νµ interacons in maer (maer effects, A terms) 26/08/2015, INSS K.Mahn, Acc-nu sources 12 Oscillaon probabilies Oscillation probabilities

νµ to νe appearance probability expansion:

E A =2 2G N F e m2 32

Key players: 2 -3 2 § |Δm 32|~ 2.4 x 10 eV (atmospheric mass spling) § Mixing angles: θ12, θ23, θ13 Approximaon from § CP-violang phase Subleading terms of δCPνµ to νe appearance depend on δCP, mass hierarchy, but interpretaon requires precision measurements of: M. Freund, PRD 64, 053003 Δm2 , θ (disappearance) and Δm2 , θ and θ Neutrinos vs. anneutrinos probability depends on 32 23 21 δ12CP, mass hierarchy13 (sign 2 of Δm 32 ) Measurements of νµ to νe (and νµ to νe ) appearance are sensive to • Mass hierarchy is determined through energy dependence of currently unknown physics νe, νµ interacons in maer (maer effects, A terms) 26/08/2015, INSS K.Mahn, Acc-nu sources 13 Oscillation probabilities

2 2 2 ( 1.27Δm32 L + P(νµ → ν µ ) ≅ 1− sin 2θ23 sin * - ) E ,

2 2 Measure: Δm 32 and sin 2θ23 Experimental controls: § Fix beam energy (E) € § Place a detector at L, the (first) oscillaon maximum

Why not place two detectors, one at L and one at 2L? P(ν ) µ Flux decreases as 1/L2:

Osc maximum Event rate scales with flux: N = Φ x σ x ε P(ν ) ξ Event rate is (currently) too small

26/08/2015, INSS K.Mahn, Acc-nu sources KARMEN website graphic 14 Long baseline experiments

2 2 2 ( 1.27Δm32 L + P(νµ → ν µ ) ≅ 1− sin 2θ23 sin * - +... ) E ,

Unknown road to Unknown road - Google Maps http://maps.google.com/maps?hl=en&tab=wl Δm2 ~3x10-3 eV2, want sin2(Δm2 L/E) to be of order 1 32 To see all the details that are visible on the screen, use the "Print" link next to the map. Tokai To € Kamioka (T2K) experiment: MINOS experiment: Eν(peak) ~0. 6GeV, L=295km Eν(peak) ~3 GeV, L=735km

First part of lecture: What are the physics results from long baseline experiments?

©2011 Google - Imagery ©2011 TerraMetrics -

26/08/2015, INSS K.Mahn, Acc-nu sources 15

1 of 1 4/23/11 10:27 AM Accelerator-basedThe Tokai-to- Kamiokaexperiment experiment example: T2K

The physics so far:

νµ to νe (and νµ to νe) appearance: § Discovery of νe appearance (2013) § Search for presence of appearance Neutrino flux at SK with anneutrinos; necessary step (no oscillaon) toward future CPV searches

νµ, νµ disappearance: § World’s best measurement of θ23 § With anneutrinos: test of NSI or CPT theorem

26/08/2015, INSS K.Mahn, Acc-nu sources 16 νµ disappearance at T2K

For a fixed baseline (L=295km) 2 2 2 ( 1.27Δm32 L + oscillaon probabilies depend on P(νµ → ν µ ) ≅ 1− sin 2θ23 sin * - +... ) E , the neutrino energy Eν

2 2 Data Extract Δm , sin θ23 from observed 60 change in overall rate and spectrum MC€ Unoscillated Spectrum 40 MC Best Fit Spectrum § Energy esmated using

NC MC Prediction

Events/0.10 GeV momentum, angle and assumed 20 CCQE kinematcs

0 0 2 4 > 5 PRD 91, 072010 (2015) Reconstructed ν Energy (GeV) 10

1

10−1

10−2 0 2 4 > 5

Osc. to unosc Events/0.1 GeV Reconstructed ν Energy (GeV)

26/08/2015, INSS K.Mahn, Acc-nu sources 17 T2K observed event distributions) 4 /c 2 T2K data favors maximal disappearance 3.2 eV -3 § Provides best constraint on θ to date, SK joint OA

23 (10 3 consistent with maximal (45°) mixing 2 32 m ∆ 2.8 T2K joint OA

2.6

2.4

2.2 MINOS joint OA

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 ) 4 -2 /c 2 eV -3 -2.2 MINOS joint OA (10 2 32 PRD 91, 072010 (2015) m -2.4 ∆

-2.6

-2.8 T2K joint OA

-3 SK joint OA

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 2 sin θ23 26/08/2015, INSS 18 K.Mahn, Acc-nu sources T2K observed event distributions) 4 /c 2 T2K data favors maximal disappearance 3.2 eV -3 § Provides best constraint on θ to date, SK joint OA

23 (10 3 consistent with maximal (45°) mixing 2 32 m ∆ § Atmospheric measurements also 2.8 T2K joint OA important (SK, IceCube) 2.6 Best constraint on mass spling from MINOS experiment 2.4 • Energy uses lepton and hadronic state 2.2 MINOS joint OA

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 ) 4 -2 /c 2 eV -3 -2.2 MINOS joint OA (10 2 32 PRD 91, 072010 (2015) m -2.4 ∆

-2.6

-2.8 T2K joint OA

-3 SK joint OA Phys. Rev. D 85, 031103(R) (2012) 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 Phys. Rev. Le. 101, 131802 (2008) 2 sin θ23 26/08/2015, INSS 19 Phys.Rev.D71:112005 (2005) K.Mahn, Acc-nu sources T2K observed event distributions

New! NOvA first results § Compelling measurement with only 7.6% of total data expected § Consistent with T2K and MINOS + atmospheric measurements

M. Sanchez, NuFact2015 26/08/2015, INSS 20 K.Mahn, Acc-nu sources T2K observed event distributions New! T2K first anneutrino disappearance results § Probe of NSI; consistent with neutrino measurement

34 events seen, 34 expected

26/08/2015, INSS 21 K.Mahn, Acc-nu sources Oscillaon probabilies νe appearance

νµ to νe appearance probability depends on all other mixing parameters

PRD 91, 072010 (2015)

Understanding δCP currently requires informaon about θ23 (and mass hierarchy)

Crical input from reactor measurements of θ13 26/08/2015, INSS K.Mahn, Acc-nu sources 22 Oscillaon probabilies νe appearance

νµ to νe appearance probability depends on all other mixing parameters

NOnA 1s and 2s Countours for Starred Point NOnA NOnA Nominal Run 810km Baseline 3.6E21 PoT n + n 2 sin 2q13=0.09 0.08 2 § Ellipse maps out how sin 2q23=1.00 A. Norman H L δCP changes the Neutrino 2014 oscillaon probability Inverted § Comparisons between 0.06 Ê neutrino/anneutrino

L · e

appearance oscillaon n Æ m

probabilies will be used n Á H to infer δ , mass P 0.04 Ê CP ‡ Á hierarchy 2s · 1s ¯‡ 0.02 Normal

Á d=0 Ê d=p 2 · d=p ‡ d=3p 2 0.00 0.00 0.02 0.04 0.06 0.08 ê

P nmÆne ê 26/08/2015, INSS K.Mahn, Acc-nu sources 23 H L Oscillaon probabilies νe appearance

νµ to νe appearance probability depends on all other mixing parameters

NOnA 1s and 2s Countours for Starred Point NOnA NOnA Nominal Run 810km Baseline 3.6E21 PoT n + n 2 0.08 sin 2q13=0.09 sin22q =0.95 § Ellipse maps out how 23 A. Norman H L δCP changes the Neutrino 2014 oscillaon probability Ê § Comparisons between 0.06 · Á neutrino/anneutrino Inverted L e appearance oscillaon n ‡Ê

Æ Ê m n

probabilies will be used H Á 2s

P 0.04 · to infer θ23 octant · 1s Á Ê ¯‡ Á ‡ · 0.02 ‡ Normal Á d=0 Ê d=p 2 · d=p ‡ d=3p 2 0.00 0.00 0.02 0.04 0.06 0.08ê

P nmÆne ê

26/08/2015, INSS K.Mahn, Acc-nu sources 24 H L T2K νe appearance

2 Fit to νe candidates’ rate and 2 2 2 ' 1.27Δm31L * kinemac distribuons to P(νµ → νe ) ≅ sin 2θ13 sin θ23 sin ) , ( E + determine oscillaon parameters

Signal # events Signal: CC νe candidates 2 @sin 2θ13=0.1,δcp=0 €21.06 from νµ to νe oscillaon 2 -3 2 2 νε signal@Δm 32 =2.4 x 10 eV , sin 2θ23=1.0 For T2K neutrino data set Tag νe by selecng -like rings Background # events (proton below threshold)

beam νe + νe 3.54 CCπ CCQE νe

νµ + νµ (mainly NC) 1.43 ν e ν background total: 4.97 W W n p π N Δ N’

26/08/2015, INSS K.Mahn, Acc-nu sources 25 T2K νe appearance

2 Fit to νe candidates’ rate and 2 2 2 ' 1.27Δm31L * kinemac distribuons to P(νµ → νe ) ≅ sin 2θ13 sin θ23 sin ) , ( E + determine oscillaon parameters

Signal # events Signal: CC νe candidates 2 @sin 2θ13=0.1,δcp=0 €21.06 from νµ to νe oscillaon 2 -3 2 2 νε signal@Δm 32 =2.4 x 10 eV , sin 2θ23=1.0 For T2K neutrino data set Tag νe by selecng electron-like rings Background # events (proton below threshold)

beam νe + νe 3.54 CCπ CCQE νe

νµ + νµ (mainly NC) 1.43 ν e ν background total: 4.97 W W Data event: n p π N Δ single electron N’

26/08/2015, INSS K.Mahn, Acc-nu sources 26 T2K νe appearance

2 Fit to νe candidates’ rate and 2 2 2 ' 1.27Δm31L * kinemac distribuons to P(νµ → νe ) ≅ sin 2θ13 sin θ23 sin ) , ( E + determine oscillaon parameters

Signal # events Background: CC νe candidates 2 @sin 2θ13=0.1,δcp=0 €21.06 Irreducible νe produced in beam 2 -3 2 2 νε signal@Δm 32 =2.4 x 10 eV , sin 2θ23=1.0 For T2K neutrino data set Idencal to signal except for Eν dependence Background # events

beam νe + νe 3.54

νµ + νµ (mainly NC) 1.43 background total: 4.97

26/08/2015, INSS K.Mahn, Acc-nu sources 27 T2K νe appearance

2 Fit to νe candidates’ rate and 2 2 2 ' 1.27Δm31L * kinemac distribuons to P(νµ → νe ) ≅ sin 2θ13 sin θ23 sin ) , ( E + determine oscillaon parameters

Signal # events Background: NC with a π0 2 0 @sin 2θ13=0.1,δcp=0 €21.06 π decay to two photons; single photon 2 -3 2 2 νε signal@Δm 32 =2.4 =2.4 x 10x 10 eV , sin 2θ23=1.0 mimics CC νe (electromagnec shower) in For T2K neutrino data set Cherenkov detector

Background # events NCπ0 beam ν + ν 3.54 e e ν ν

νµ + νµ (mainly NC) 1.43 background Z

total: 4.97 N π Δ N’

26/08/2015, INSS K.Mahn, Acc-nu sources 28 T2K νe appearance

2 Fit to νe candidates’ rate and 2 2 2 ' 1.27Δm31L * kinemac distribuons to P(νµ → νe ) ≅ sin 2θ13 sin θ23 sin ) , ( E + determine oscillaon parameters

Signal # events Background: NC with a π0 2 0 @sin 2θ13=0.1,δcp=0 €21.06 π decay to two photons; single photon 2 -3 2 2 νε signal@Δm 32 =2.4 =2.4 x 10x 10 eV , sin 2θ23=1.0 mimics CC νe (electromagnec shower) in For T2K neutrino data set Cherenkov detector

Background # events NCπ0 beam ν + ν 3.54 e e ν ν

νµ + νµ (mainly NC) 1.43 background Z

total: 4.97 N π MC event: Δ π0 N’

26/08/2015, INSS K.Mahn, Acc-nu sources 29 T2K νe appearance results

Data 28 candidate events observed 8 Best fit νe Background component § First observaon of CC νe appearance! 6 Fit region < 1250 MeV § Phys. Rev. Le. 112, 061802 (2014)

4 candidate events

e Signal # events ! 2 2 @sin 2θ13=0.1,δcp=0 21.06

0 0 500 1000 1500> 2000

Number of Reconstructed neutrino energy (MeV) Background # events

beam νe + νe 3.54

νµ + νµ (mainly NC) 1.43 background total: 4.97

26/08/2015, INSS K.Mahn, Acc-nu sources 30 Antineutrino appearance analysis T2K antineutrino appearance results

Normal hierarchy Inverted hierarchy Expect 3.73 (4.18) events based on β scales green normal (inverted) hierarchy

Test of no νe appearance hypothesis: • Significant expected contribuon from νe appearance

• β=0: no νe appearance • β=1: νe appearance

7/24/2015 K. Mahn, FNAL W&C seminar 31 Rate only p-value and sensitivity T2K antineutrino appearance results

Generate an ensemble of test experiments with β=0 (no νe appearance) § p-value: fracon of test experiments that have as many or more candidate events as T2K data § Sensivity: mean p-value for an ensemble of fake data experiments with β=1

Rate p-value Likelihood only rao Data: 0.26 0.9 3 events

Likelihood rao: L(β=0)/L(β=1) is close to 1

Data does not favor or disfavor νe appearance

7/24/2015 K. Mahn, FNAL W&C seminar 32

3 2 Rate+shape distribution of candidate events T2K antineutrino appearance results

Signal only Background only ( = 0) 2ln = 2lnLmarg L ( = 1) Lmarg

Data does not favor or disfavor νe appearance

7/24/2015 K. Mahn, FNAL W&C seminar 33

3 3 NOvA νe appearance results

M. Sanchez, NuFact2015

6, 11 candidate νe events observed with two selecons in tracking detector § Also signal dominated (~1 event background) § 3.3σ/5.5σ evidence for

CC νe appearance § Consistent with T2K

26/08/2015, INSS K.Mahn, Acc-nu sources 34 NOvA νe appearance results

Electromagnec shower of one candidate M. Sanchez, NuFact2015

6, 11 candidate νe events observed with two selecons § Also signal dominated (~1 event background) § 3.3σ/5.5σ evidence for

CC νe appearance § Consistent with T2K

26/08/2015, INSS K.Mahn, Acc-nu sources 35 Aside 1: blind analyses

In a blind analysis, the analysers: § Perform all checks and cross checks required prior to looking at the data; prevents tuning away or enhancing signals § Report any changes post-unblinding § Example: Expect nue appearance. Hide the expected nue appearance signal in a ‘box’ unl the enre analysis chain is prepared and reviewed. Then, count the number of nue candidates § Possible bias: § Revising event selecon aer seeing the data § Could try to reject events (because you want no signal events) or add events to the sample (because you want a signal, this one’s close enough!)

Blindness is to avoid bias, addional resources in backups

NOvA used this for their first results

26/08/2015, INSS K.Mahn, Acc-nu sources 36 Aside 2: trials factor

NOvA sees 6 events with one selecon, and 11 events with another selecon § ``Beware of trials factor for choosing 11 events aer the fact’’

Trials factor: With large data sets, expect some number of anomalies (stascally) • Example: 200 medical researchers test 200 drugs. One researcher finds a stascally significant effect at the 99.9% C.L., and publishes. The other 199 find nothing, and publish nothing. • But, chance of one drug giving a false signal: 0.1%. • Chance that at least one of 199 drugs will give a significant result at this level: 18%

NOvA chose the primary analysis in advance of seeing the event rate, so avoided the risk of choosing the more excing answer aer the fact

Report what you measure!

26/08/2015, INSS K.Mahn, Acc-nu sources 37 Global picture of νe appearance

Long baseline experiments depend on δCP + θ13 + … Reactor experiments are pure measurements of θ13 Large number of events observed by T2K, NOvA restrict allowed hierarchy + δCP 1

0.5 ⇥ / 0 CP ⇤

-0.5

PRD 91, 072010 (2015) -1 0.02 0.04 0.06 0.08 0.1 2 sin (13)

T2K+Reactor 68% Credible Region T2K Only 68% Credible Region T2K+Reactor 90% Credible Region T2K Only 90% Credible Region T2K+Reactor Best Fit Point T2K Only Best Fit Line

26/08/2015, INSS K.Mahn, Acc-nu sources 38

2 2 α = Δm 12/Δm 32 ~ 0.04 2 2 Δm 31 ~ Δm 32 Global picture of νe appearance

§ T2K, NOvA favors δCP around 3π/2 at 90%CL, disfavored by MINOS? § But hierarchy is not determined due to entanglement with δCP and octant § Not strong statements yet!

PRD 91, 072010 (2015)

2 2 Probability Δm 32>0 Δm 32<0 Sum

2 sin θ23 ≤ 0.5 16.5% 20.0% 36.5%

2 > 0.5 sin θ23 28.8% 34.7% 63.5% Sum 45.3% 54.7% 26/08/2015, INSS K.Mahn, Acc-nu sources 39

2 2 α = Δm 12/Δm 32 ~ 0.04 2 2 Δm 31 ~ Δm 32 Future νe appearance results

T2K collab, arXiv:1409.7469, accepted by PTEP

NOνA’s higher energy (peak Eν~2 GeV) and longer baseline (L~810km) has a different dependence on mass hierarchy through the maer effect than T2K’s § Gray regions are where the mass hierarchy can be determined to 90% CL for T2K(red), NOνA (blue), and T2K+NOνA (black) for full run of both experiments rd § 95%CL determinaon for 1/3 of δCP space for maximal θ23 Unknown complicaons of θ23 and δCP in this equaon mean 26/08/2015, INSS mulple experiments are K.Mahn, Acc-nu sources complementary 40 The OPERA experiment

On-axis beam (Eν≈17 GeV) CERN to Gran Sasso, Italy (730km)

OPERA physics run: Operated from 2008-2012 Neutrinos: 1.8x1020 POT

Measurements of:

ντ appearance

OPERA plots from S. Dusini, Neutrino2014

26/08/2015, INSS K.Mahn, Acc-nu sources 41 OPERA ντ appearance results

Emulsion film + lead form “bricks” § Scinllator planes and magnec spectrometer are used to idenfy likely neutrino interacon bricks § Bricks removed and scanned to determine τ decay candidate interacons § precise vertex informaon ντ appearance expected signal 2.10±0.4, background 0.23±0.04 Observed 4 candidate events (no oscillaon excluded at 4.2σ)

26/08/2015, INSS K.Mahn, Acc-nu sources 42 A third appearance experiment

LSND Experiment: observaon of 3.8σ excess of νe in νµ beam “Short baseline”: Eν ~30 MeV, L~30m νe detected with inverse beta decay and delayed n capture 2 2 2 2 There are two independent Δm , as Δm 21 + Δm 32= Δm 31 2 2 2 -5 2 2 -3 2 LSND observed Δm ~ 1eV >> Δm21 (10 eV ) + Δm 32 (10 eV ) Inconsistent with just three mass eigenstates, is it new physics?

26/08/2015, INSS K.Mahn, Acc-nu sources 43 A third appearance experiment

LSND Experiment: observaon of 3.8σ excess of νe in νµ beam “Short baseline”: Eν ~30 MeV, L~30m νe detected with inverse beta decay and delayed n capture 2 2 2 2 There are two independent Δm , as Δm 21 + Δm 32= Δm 31 2 2 2 -5 2 2 -3 2 LSND observed Δm ~ 1eV >> Δm21 (10 eV ) + Δm 32 (10 eV ) Inconsistent with just three mass eigenstates, is it new physics?

Second part of lecture: What are the physics results from short baseline () experiments?

26/08/2015, INSS K.Mahn, Acc-nu sources 44 Sterile neutrinos One explanaon for the LSND oscillaon signal is to add another “sterile” flavor of neutrino (or 2 or N) to the mixing matrix: Adding 1 sterile neutrino is 3+1, adding N is 3+N

$ νe ' $ν1 ' $U U " U ' &ν ) e1 e2 eN & ) µ & ) ν2 & ) Uµ1 Uµ2 " UµN & ) Uαi = & ντ ) & ) &ν3 ) &Uτ1 Uτ1 " UµN ) &! ) &! ) & ) %& ! ! # ! () & ) %& ν () &ν ) s % N ( 3+1 oscillaon probability: 2 2 2 2 % 1.27Δm41L( P(νµ → νe ) = 4 |Ue4 | |Uµ 4 | sin ' * & E )

2 W.C. Louis, 2 2 2 & 1.27Δm41L) P(νµ → ν x ) = 1− 4 |Uµ 4 | (1− |Uµ4 | )sin ( + Nature, Volume: 478, ' E * Pages: 328–329 €

€ 26/08/2015, INSS K.Mahn, Acc-nu sources 45 The Booster Neutrino Experiments (BooNEs)

• MiniBooNE placed for maximal LSND oscillaon 2 (541 m at 1 GeV; Δm ~ 1eV2) • Different signal idenficaon, systemacs • SciBooNE reused from earlier experiments Beamline now to be used for short baseline neutrino program (SBN)

MiniBooNE target decay SciBooNE 541m Booster horn volume 100m

26/08/2015, INSS K.Mahn, Acc-nu sources 46 MiniBooNE νe appearance analysis

Signal (Dm2=1eV2, sin22q=0.004) Background 0 § misidentified νµ (mainly π s) + § νe from µ decay + 0 § νe from K , K decay § Δ ⇒ Νγ § External backgrounds

Similar to T2K appearance analysis:

• Backgrounds from NC, intrinsic νe

Main difference: much smaller oscillaon probability (0.25%), background dominated

26/08/2015, INSS K.Mahn, Acc-nu sources 47 € • • of Lack

Events/MeV Events/MeV

0.0 0.5 1.0 1.5 2.0 2.5 0.2 0.4 0.6 0.8 1.0 1.2 26/08/2015, INSS ...... 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 Photon background? background? Photon to signal 3+1 mapped not well neutrinos, in tension drives excess energy Low ν µ

→ ν e appearance but observation of but observation appearance MiniBooNE ν MiniBooNE Neutrino Antineutrino MicroBooNE Constr. Syst.Error other dirt Data (staterr.) 0 e e e

misid from fromK fromK N µ +/- 0 +/- K.Mahn, Acc-nu sources 1.5 E QE e (GeV) appearance results appearance to test 3.0 €

Excess Events/MeV Excess Events/MeV -0.2 0.0 0.2 0.4 0.6 0.8 0.0 0.2 0.3 0.4 0.1 ...... 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 ν µ

→ ν e

appearance appearance MiniBooNE 2 sin sin Data -expectedbackground 2 2 2 2 =0.004, =0.2,

Antineutrino Neutrino m BestFit 2 m =0.1eV 2 =1.0eV 2 2 1.5 48 E QE /GeV 3.0 Global νe appearance results

§ 2 Neutrino data fit: PRL 98:231801,2007 )

2 10 § LSND 90% CL Anneutrino data fit: PRL 105:181801,2010 (eV 2 LSND 99% CL m

§ Combined fit of neutrino and anneutrino data KARMEN2 90% CL 10 have 3.8σ signal for ν → ν appearance 68% µ e 90% § PRL 110, 161801 (2013) 95% 1 99% ICARUS experiment (~730km flight distance, 20 GeV neutrinos) sees no evidence for appearance € 10-1 § Eur. Phys. J. C (2013) 73:2345 Antineutrino )

§ Will move to beamline at FNAL for addional 2 (eV

tests 2 m 10 ICARUS 90% CL

1

10-1 Neutrino

10-2 10-3 10-2 10-1 1 sin22 26/08/2015, INSS K.Mahn, Acc-nu sources 49 Sterile neutrinos One explanaon for the LSND oscillaon signal is to add another “sterile” flavor of neutrino (or 2 or N) to the mixing matrix: Adding 1 sterile neutrino is 3+1, adding N is 3+N

$ νe ' $ν1 ' $U U " U ' &ν ) e1 e2 eN & ) µ & ) ν2 & ) Uµ1 Uµ2 " UµN & ) Uαi = & ντ ) & ) &ν3 ) &Uτ1 Uτ1 " UµN ) &! ) &! ) & ) %& ! ! # ! () & ) %& ν () &ν ) s % N ( 3+1 oscillaon probability: 2 2 2 2 % 1.27Δm41L( P(νµ → νe ) = 4 |Ue4 | |Uµ 4 | sin ' * & E )

2 W.C. Louis, 2 2 2 & 1.27Δm41L) P(νµ → ν x ) = 1− 4 |Uµ 4 | (1− |Uµ4 | )sin ( + Nature, Volume: 478, ' E * Pages: 328–329 €

€ 26/08/2015, INSS K.Mahn, Acc-nu sources 50 Disappearance at SciBooNE and MiniBooNE

Consider a 3+1 oscillaon model: 2 2 2 ( Δm L+ P(νµ → ν x≠µ ) ≅ sin 2θ sin * - ) 4E ,

2 2 Below Δm ~0.5 eV , νµ have not oscillated yet € At 0.5 < Δm2 < 2 eV2, events at MiniBooNE undergo oscillaon

At 2 < Δm2 < 30 eV2, events at SciBooNE also undergo oscillaon

Above Δm2~30 eV2, oscillaon is an overall normalizaon change, where MiniBooNE/SciBooNE are insensive

26/08/2015, INSS K.Mahn, Acc-nu sources 51

Oscillation probability vs neutrino energy Rao of oscillated spectrum to unoscillated (sin22θ = 0.10) Disappearance observable 2 2 2 2 as a deficit and distoron 1.04 "m2=0.5eV2 1.04 "m2=1eV2 1.04 "m =6eV 1.04 "m =9eV 1.02 1.02 1.02 1.02 to neutrino energy 1 1 1 1 spectrum 0.98 0.98 0.98 0.98 0.96 0.96 0.96 0.96 0.94 0.94 0.94 0.94 Includes: 0.92 0.92 0.92 0.92 0.9 0.9 MiniBooNE CCQE ν 0.9 MRD stopped 0.9 - Oscillaon of all CC ν µ 0.88 0.88 0.88 µ 0.88 SciBar stopped interacons at SciBooNE 0.86 0.86 0.86 0.86 0.5 1 1.5 0.5 1 1.5 0.5 1 1.5 0.5 1 1.5 and MiniBooNE reconstructed E (GeV) reconstructed E (GeV) reconstructed E! (GeV) reconstructed E! (GeV) ! ! - Distribuon of distance 1.04 2 2 1.04 2 2 22 2 2 1.04 "m2=2eV2 1.04 "m2"=3eVm =6eV2 1.04 ""mm=30eV=9eV 1.04 "m =90eV travelled by neutrinos (L) 1.02 1.021.02 1.021.02 1.02 1 1 1 11 1 0.98 Mean L 0.980.98 0.980.98 0.98 0.96 0.960.96 0.960.96 0.96 SciBooNE 0.94 ~76m 0.940.94 0.940.94 0.94 0.92 0.920.92 0.920.92 0.92 MiniBooNE 0.9 ~520m 0.9 0.9 0.90.9 0.9 0.88 0.880.88 0.880.88 0.88 ~50m spread in L due 0.86 0.860.86 0.860.86 0.86 0.5 1 1.5 0.5 1 1.5 to finite decay volume 0.5 1 1.5 0.5 1 1.5 0.5 1 1.5 0.5 1 1.5 reconstructed E! (GeV) reconstructedreconstructed E E !(GeV) (GeV) reconstructed E (GeV) reconstructed E! (GeV) reconstructed E! (GeV) ! ! 1.04 "m2=30eV2 1.04 "m2=90eV2 26/08/2015, INSS 1.02K.Mahn, Acc-nu sources 1.02 52 1 1 0.98 0.98 0.96 0.96 0.94 0.94 0.92 0.92 0.9 0.9 0.88 0.88 0.86 0.86 0.5 1 1.5 0.5 1 1.5

reconstructed E! (GeV) reconstructed E! (GeV) SciBooNE CC νµ data set SciBar stopped MRD stopped 4500 3000 Data Data Events

4000 Events Null oscillation 2500 Null oscillation 3500 Non-CCQE events 3000 2000 Non-CCQE events 2500 1500 2000

1500 1000 1000 500 500

0 0 o 1.5

o 1.5 1.4 Best fit 1.4 Best fit Rati 2 2 2 Rati 2 2 1.3 # m = 1.0 eV , sin 2" = 0.5 # m2 = 1.0 eV , sin 2" = 0.5 2 2 2 1.3 # m = 10 eV , sin 2" = 0.5 # m2 = 10 eV2, sin22" = 0.5 1.2 1.2 1.1 1.1 1 1 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0.5 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Reconstructed E (GeV) ! Reconstructed E! (GeV) First, test agreement of SciBooNE datasets: § No evidence for oscillaon at SciBooNE Error bands include neutrino flux, cross secon and detector uncertaines

26/08/2015, INSS K.Mahn, Acc-nu sources 53 Ratio Events 25000 30000 10000 15000 20000 5000 0.5 1.4 1 0.6 0.7 0.8 0.9 1.2 1.3 1.1 . + predicon (no oscillaon) MiniBooNE CCQE 5 0 1 26/08/2015, INSS ...... 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0

Best fit # # m m 2 2 =10.0eV =1.0eV MiniBooNE CCQE MiniBooNE ν µ

data set 2 , sin 2 , sin 2 Reconstructed E 2 2 2 " =0.5 Non-CCQE events Null oscillation Data " =0.5 K.Mahn, Acc-nu sources ! (GeV) ν Fit 16+16+16 bins in total = 48 techniques) (esmated from Δχ Δχ At χ χ 2 2 µ

(best) = 39.5/ 46 (DOF) (null) = 45.1/ 48 (DOF) 2 2

data set data = χ Δm (90% CL, null) = 9.3 2 2 (null) = 43.7 eV – χ 2

frequenst

2 (best) = 5.6 , sin 2 2θ = 0.60

54 Non-standard νµ disappearance results Joint search for non standard disappearance with MiniBooNE and SciBooNE data

is consistent with no νµ or νµ disappearance at 90%CL 2 ]

2 10 [eV 2 m "

90% CL limits from CCFR and CDHS Excluded to the 10 MiniBooNE only 90% CL limit 90% CL limit from MINOS right of the curve 90% CL sensitivity (Sim. fit) 90% CL observed (Sim. fit)

90% CL observed (Spec. fit)

1 Neutrino 2012

Phys. Rev. D 85, 032007 (2012) Phys. Rev. Le. 107, 011802 (2011) 10-1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 sin2 2 !

26/08/2015, INSS K.Mahn, Acc-nu sources 55 Short baseline physics at long baseline

The presence of a sterile neutrino would produce a deficit of acve flavors at the far detector (NC deficit)

2 ]

2 10 [eV 2 m "

90% CL limits from CCFR and CDHS 10 MiniBooNE only 90% CL limit 90% CL limit from MINOS

90% CL sensitivity (Sim. fit) 90% CL observed (Sim. fit)

90% CL observed (Spec. fit)

1 Green limit from MINOS NC far detector events • Consistent with expected flux, and no sterile mixing

10-1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 sin2 2 ! 26/08/2015, INSS K.Mahn, Acc-nu sources 56 Short baseline physics at long baseline

MINOS+ website

MINOS+ experiment running concurrent with NOvA can expand the sterile search

Tension between SBL CC, LBL NC disappearance results and SBL CC appearance results

26/08/2015, INSS K.Mahn, Acc-nu sources 57 NSI long baseline physics MINOS+ experiment running concurrent with NOvA will also use CC samples to probe steriles, NSI mixing (large extra dimensions) • MINOS has done tests of NSI coupling as well already

MINOS+ website

26/08/2015, INSS K.Mahn, Acc-nu sources 58 First lecture summary (Some of) the rich physics which uses neutrino beams § Consistent picture emerging of three acve flavor mixing § Puzzles remain for non standard ν oscillaon such as sterile ν

Next lecture: the devil is in the details § How do we build neutrino beams? § What are the challenges of performing experiments?

Quesons? Want to know more about a parcular topic? S. Gilardoni Let’s talk! INSS09

26/08/2015, INSS K.Mahn, Acc-nu sources 59 Backup slides

26/08/2015, INSS K.Mahn, Acc-nu sources 60 Blindness resources

Thanks to S. Oser

26/08/2015, INSS K.Mahn, Acc-nu sources 61 MiniBooNE (wide-band) neutrino flux

-8 Neutrino flux !µ mode Anneutrino flux

) 10 2

-9

/POT/GeV/cm 10 ! ) ( ! (E " -10 10 SciBooNE MiniBooNE

-11 10

-12 10

-13 10 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

E! (GeV) neutrino energy (Eν ) in GeV Predominantly ν µ Significant neutrino § + ~6% νµ , ~0.5% νε νε component to anneutrino running

In MiniBooNE: ~1 ν per 1e15 POT condion (~16% νµ in flux) In SciBooNE: ~0.5 ν per 1e15 POT ~5x closer, ~50x smaller 26/08/2015, INSS K.Mahn, Acc-nu sources 62