PoS(ICRC2017)1026 http://pos.sissa.it/ ∗ [email protected] Speaker. A new analysis, aimed at improving thetrino current oscillation ANTARES measurement parameters, of is the presented atmospheric in neu- theseprocedures proceedings. are Two different combined track in reconstruction orderestimate the to neutrino increase energy is the applied. sensitivity.ability A including complete Furthermore, matter 3-flavour description effects a of in novel the theevent method oscillation rate Earth prob- as to is a function used. of reconstructed By energythe performing and oscillation zenith a parameters angle, two-dimensional expectations are fit on derived. the of Using sensitivitysensitivity the to the to same sterile analysis neutrinos is chain, performed. a study on the ANTARES ∗ Copyright owned by the author(s) under the terms of the Creative Commons c Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). 35th International Cosmic Ray Conference -10-20 ICRC2017- July, 2017 Bexco, Busan, Korea Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille,E-mail: France On behalf of the ANTARES Collaboration I. Salvadori Sensitivity of the ANTARES neutrino telescopeatmospheric to neutrino oscillation parameters PoS(ICRC2017)1026 2 32 m ∆ I. Salvadori are the ele- i α ) and a CP vio- U 13 θ , 23 θ , 12 θ ) ) ) L L L 2 12 2 31 2 32 m m m E E E ∆ ∆ ∆ 27 27 27 . . . 1 1 1 ( ( ( 2 2 2 is its energy (in GeV), the parameter space which can be tested the mechanism of neutrino oscillations 5 m. The horizontal spacing among the . ) is the absolute difference of the squares E sin sin sin 7 2 2 2 2 2 and the ANTARES sensitivity for the | | | ), which are the ones taking part in interac- 2 3 3 5 τ µ µ µ ν , U U U | | | (in eV µ 2 2 2 | | | | ν 1 in the 3 flavour scenario can be written as: j 2 1 1 2 , e µ µ µ µ m ν ν . In Section U U U | | | − 6 4 4 4 ] is situated in the Mediterranean Sea, 40 km from the 2 i 1 − − − m | , together with the details of the event selection; a discussion = 1 4 2 i j = m µ ∆ ν → µ ν ]. ), which are used to describe neutrino propagation through space, are not P 3 [ 3 the MC simulations are described; the track and energy reconstruction ν , 3 2 . ν 8 , 1 ], and can be parameterized by three mixing angles ( ν 2 ). OscProb CP δ is the distance traveled by the neutrino (in km), parameters are presented in Section L 23 The survival probability of atmospheric The official Monte Carlo (MC) production of ANTARES has been used for this work, which Neutrino oscillation is a quantum mechanical phenomenon, which occurs since the neutrino The document is organized as follows: in Section In this work, a complete 3 flavour framework is used, and the survival probabilities of atmo- The ANTARES neutrino telescope [ θ disappearance due to neutrino oscillations, and constraints on atmospheric neutrino oscillation µ simulates individual data acquisition ”runs” from 2007 to 2015. A total lifetime of around 2236 lating phase ( 3. Monte Carlo Simulations the same as the neutrino flavour eigenstates ( mass eigenstates ( is recalled; in Section of the minimization procedure is described inand Section under the assumption of the existenceare of given in a Section sterile neutrino is obtained. Conclusions and prospects 2. Neutrino Oscillations where ments of the PMNS matrix, and procedures are explained in Section spheric muon neutrinos including Earthsource software matter effects are computed numerically using the open coast of Toulon (France). Itof is 3 composed optical modules of (OMs), 12 withlines detection is a lines, around vertical 60 each spacing m. one of The equipped 14 galactic main with goal and of 25 extra-galactic ANTARES is floors sources. the observation Theof of detector energies high energy is, up neutrinos to for from TeV, this byin reason, detecting neutrino the optimized interactions. Cherenkov to photons detect On emitted neutrinos theconfiguration by other charged and hand, particles the at produced neutrino reconstructionν energies algorithms of allow the to order of studyparameters GeV, the the can be detector phenomenon derived. of atmospheric tions. The relation between these two bases(PMNS) is matrix described [ by the Pontecorvo-Maki-Nakagawa-Sakati of the mass eigenstates. ANTARES Atmospheric Neutrino Oscillations 1. Introduction PoS(ICRC2017)1026 2 ], eV 10 class 3 − 10 I. Salvadori ] and [ ROOT × 9 has been fitted, 43 . 2 13 ] software, devel- ]. The ]. θ 4 = [ 7 12 2 32 m ∆ model [ GENHEN PREM minimization in order to find the values of the 2 χ 2 because is close to the current global best fit value 23 θ for each different hypothesis with respect to the test point. 2 χ a complete list of all the fitted parameters together with their test values 1 , is left free to account for these systematic effects. Also ]. The expected sensitivity of the analysis to the oscillation parameters has N 11 has been used to perform the . We chose such a value of ◦ 5 . ] software is used. Atmospheric muons wrongly reconstructed as up-going represent 6 [ 41 = ], if not otherwise specified. For the simulation of atmospheric muon bundles, instead, the m for minimum ionising muons in sea water, the muon energy is computed. 23 5 / The Earth density profile has been paramterized using the MC events have been binned in a 2-dimensional histogram with 100 logarithmic bins in re- Two different track reconstruction algorithms have been combined in the analysis, in order to Starting from the reconstructed muon direction, a hit selection based on spatial and time dis- In order to reduce the contamination due to atmospheric muons, only events reconstructed The minimization procedure depends on multiple parameters which affect the oscillation pat- θ for this parameter [ and eventual prior is presented. and Minuit2Minimizer constructed muon energy, from 0.1angle, to from 200 -1 GeV, and to 21 0.2. binsof A in a pseudo-data reconstructed real sample, cosine data i.e. of samplesimulations a the collected number assuming zenith in of the the events values with detector of the lifetime atmospheric same of characteristic oscillation 2236 parameters days, has been created using MC 5. Minimization Procedure then been tested by computing the increase the sensitivity. A detailed description of the procedures can be foundtributions in is made, [ in orderphotons to are select then direct projected Cherenkov back photons toused coming the for track from the to the find muon muon the track track. firstGeV length and The estimation. last emission Taking point, into which account are the then ionisation energy loss ofas 0.24 upward-going are considered inposition the of analysis. the Requiring reconstructed a interactionrameters containment vertex, specific condition, and for based applying each on additional reconstruction the cuts procedure,0.03 based muons the on per remaining quality day. background pa- Additional decreases sources toare of negligible. about background The are atmospheric due neutrino to signal neutral-current is events, expected but to these be of around 3 neutrinos per day. 4. Event Reconstruction and Selection respectively. tern in zenith and energy,normalization apart factor, from the oscillation parameters themselves. So far, only a global MUPAGE the main background source for thisenergy, zenith study. and This multiplicity program distributions uses of parametric muons formulas arriving to at describe the the detector [ atmospheric neutrino oscillation parameters which fittrino best mass our ordering pseudo-data is sample. assumed. A normal neu- ANTARES Atmospheric Neutrino Oscillations days has been considered. Neutrinooped events in are the generated ANTARES Collaboration, using and the theyflux are [ weighted with the Honda atmospheric neutrino but with a prior. In Table PoS(ICRC2017)1026 ], − 13 23 θ I. Salvadori the sensitivity at 1 ] are also shown. 28 . 0 17 ± 41 . , respectively, and minimizing with respect 23 θ 5046 FREE FIXED 5300 FIXED FIXED 4341 FREE 8 00 FREE ...... 3 and 2 32 m ] and Super Kamiokande [ ∆ 16 ] 7 ] 2 2 2 eV eV with 2 degrees of freedom (dof). In Figure ] 0 ]]] 41 8 33 5 3 2 ◦ ◦ ◦ ◦ [ − − [ [ [ χ N 1 23 13 12 CP [10 [10 θ θ θ δ Parameter Test Point Value Prior 2 21 2 32 m m ∆ ∆ ], IceCube (DeepCore) [ 15 Result obtained from our pseudo-experiment simulating 2236 days of ANTARES lifetime. The ], T2K [ Oscillation parameters (first column), values used to construct the pseudo-data sample (second 14 , which have been computed by looping on a fine grid of values around the minimum, and The existence of additional neutrinos, which do not take part in the weak interaction but whose The sensitivity region is presented in form of confidence intervals in the parameter space 2 32 m ∆ using tabulated critical values for to the other free parameters of the fit. NOvA [ 7. ANTARES Expected Sensitivity to Sterile Neutrinos Figure 1: red-dashed curve represents the allowedthe parameter two region oscillation at parameters 90% under C.L. study The are one-dimensional contours also for shown. For comparison, results from MINOS [ 90% C.L. obtained from the analysisfrom of other the experiments. pseudo-data The sample one-dimensional usedby contours looping is are over compared the also with same shown. the grid of results They values have of been obtained Table 1: column) and eventual prior (third column). 6. ANTARES Sensitivity to the Atmospheric Neutrino Oscillation Parameters ANTARES Atmospheric Neutrino Oscillations PoS(ICRC2017)1026 1 + GeV, 3 I. Salvadori 4 10 [GeV] ν E 5 . 3 10 2 2 2 ]. Here, only the simplest 3 GeV and 8 bins in reconstructed =0.3 eV =1.0 eV =3.0 eV 2 41 2 41 2 41 2 18 , has been left free to account for m m m 2 No Sterile ∆ ∆ ∆ 10 N , while the second one, around 10 34 θ GeV to 10 10 A FIXED at 0 respectively, have been made, in order to study

1.0 0.8 0.6 0.4 0.2 0.0

8

00000000 FREE FREE FREE FIXED µ µ

-> ν ν / . P . . . . and 0 (right panel), as a function of the neutrino energy. 7.2 4 24 µ θ ν and [GeV] . ν E 2 41 ]N 7.1 2 m ]]] 0 0 0 2 ∆ ◦ ◦ ◦ 10 [ [ [ [eV N 1 24 34 14 2 41 θ θ θ m =0.00 =0.10 =0.05 Parameter Test Point Value Prior (left panel) and 34 34 34 ∆ θ θ θ 2 2 2 µ ν =0.10; sin =0.00; sin =0.05; sin 24 24 24 θ θ θ 2 2 2 sin sin sin No Sterile , and a global normalization factor, 1 10

0.8 0.6 0.4 0.2 0.0 1.0

µ µ -> ν ν P a complete list of all the fitted parameters together with their test values and eventual illustrates the effect that the existence of such a sterile neutrino would have on the 1 to 0. 2 2 − Example of the distortion caused by the presence of a sterile neutrino on the oscillation probability Oscillation parameters (first column), values used to construct the pseudo-data sample (second , from 30 GeV is sensitive to the mixing angles In Table For the lowest energy range, the same events from the considered pseudo-data sample as for Two parallel analyses, described in As shown in the figure, two different energy ranges can be studied. The first one, around Figure θ − cos the standard oscillation analysislogarithmic are bins used. in reconstructed Events energy, from have 10 been binned in a 2D histogram with 10 systematic effects. The details are presented in the following sub7.1 sections. Low Energy Analysis Table 2: column) and eventual prior (third column). the sensitivity of ANTARES to theassuming sterile no neutrino sterile; parameters. the Data standardas have been oscillation illustrated imitated parameters in with have Table MC been kept fixed to the same values prior is presented. allows to constrain the mass splitting Figure 2: pattern, for a vertical up going 20 oscillation probability of a verticallyits up energy. going muon neutrino crossing the Earth, as a function of ANTARES Atmospheric Neutrino Oscillations presence could introduce distortions inpossible the explanation oscillation for some probability neutrino patterns,model experiment has is anomalies been considered, [ which posited describes as thesterile a mixing neutrino. between the three active neutrinos with only one PoS(ICRC2017)1026 ], , as 19 23 θ I. Salvadori and 2 32 . m 3 ∆ 24 θ 2 sin has been performed. θ IC 90% CL IC 99% CL SK 90% CL SK 99% CL ANTARES sensitivity 90% CL ANTARES sensitivity 99% CL -1 10 24 in cos ANTARES PRELIMINARY . A FREE 000000 FREE 00 FREE FIXED FIXED / . . . . 1 to 0 5 − -2 10 with 2 dof. Results are shown in Figure ]N 2 2 ]]] 0 0 0 χ ◦ ◦ ◦ [ [ [ [eV N 1 24 34 14 2 41 θ θ θ m Parameter Test Point Value Prior ∆ ] has been used to weight these events. A 2D fit in 10 logarithmic ] are also shown. -3 20 21 10

have been built, by looping over a fine grid of values around the minimum, 0.00 0.30 0.25 0.20 0.15 0.10 0.05

34

sin

θ 34 2 θ 2 sin a complete list of all the fitted parameters together with their test values and eventual − 3 24 test has been performed and sensitivity confidence intervals on the reduced parameter θ Expected upper limits at 90% (dashed red) and 99% (solid red) C.L. for the analysis of our pseudo- Oscillation parameters (first column), values used to construct the pseudo-data sample (second 2 2 χ In Table It is worth to remind that the standard oscillation parameters have been kept fixed for the A For the analysis at higher energies, events reconstructed by a dedicated track reconstruction bins from 100 GeV to 10 TeV and 21 bins from Table 3: column) and eventual prior (third column). prior is presented. Figure 3: data sample. Exclusion regions areand on from the Super right Kamiokande side [ of the lines. For comparison limits from IceCube [ moment. These parameters arenext expected step to in induce this the study largest will uncertainties be in the this inclusion analysis. of the The neutrino mixing parameters, algorithm, specific for moreatmospheric energetic neutrino events, flux have [ been considered. The Bartol model for the ANTARES Atmospheric Neutrino Oscillations space sin free parameters in the fit. 7.2 High Energy Analysis and using tabulated critical values for PoS(ICRC2017)1026 , in A656 I. Salvadori 1 ) Nucl.Instrum.Meth. , 24 θ 02002 (2016). (2 2 116 sin of real data sets will include the 100001 (2016). 40 , unblinding -1 10 6 with respect to the limits presented by the IceCube 2 41 Chin. Phys. C , m ∆ IC 99% CL ANTARES sensitivity 90% CL ANTARES sensitivity 99% CL . ANTARES: the first undersea neutrino telescope The Run-by-Run Monte Carlo simulation for the ANTARES experiment 4 ANTARES PRELIMINARY -2 1 -1 have been built, by looping over a fine grid of values around the minimum. -2 10

10

Particle Data Group

41

[eV m ] 10

10 2 41 ∆

2 2 m ∆ Very Large Volume Neutrino Telescope (VLVnT-2015) ]. This can be explained considering the fact that the true energy distribution of − ) 22 24 θ 2 ] is also shown. Expected upper limits at 90% (dashed red) and 99% (solid red) C.L. for the analysis of our test has been performed and sensitivity confidence intervals on the reduced parameter ( 2 22 2 χ proceeding of 11-38 (2011). It can be seen that the sensitivity regions obtained by the study of our pseudo-data sample are A study on the sensitivity of the ANTARES neutrino telescope to the standardFurther atmospheric improvements of the analysis before the A [2] C. Patrignani et al., [1] ANTARES Collaboration, [3] https://github.com/joaoabcoelho/OscProb [4] ANTARES Collaboration, slightly shifted toward lower values of neutrino oscillation parameters has beenneutrino performed. parameters, in A two different parallel energy study ranges, has on been the conducted. sensitivity to sterile Figure 4: pseudo-data sample. Exclusion regions are onIceCube the [ right side of the lines. For comparison the 99% C.L. from Collaboration [ our selected events is peaked at lower energy. 8. Conclusions and Outlook treatment of different sources of systematic effects,and in a order refinement to of study the their quality impact cuts on for the selecting final events. result References ANTARES Atmospheric Neutrino Oscillations space sin Results are shown in Figure PoS(ICRC2017)1026 , 117 in ]. 118 , for , 023006 I. Salvadori D70 parameters Phys. Rev. Lett. , ν Phys. Rev. Lett. Appearance in MINOS , e ]. ν Phys. Rev. , . 072010 (2015). → Physics of the Earth and , µ ν in NOvA D91 , 191801 (2014). , Venice (2017). 23 θ Oscillation Analysis of the 112 e astro-ph.IM/1105.4116v1 ν ]. → Phys. Rev. µ , ν , (915-923), (2008). , Nikhef (2015). hep-ex/1410.2008 (652-662) [ and . e Disappearance and 179 ν 34 Phys. Rev. Lett. µ 7 , ν → hep-ph/1601.07777v1 ]. , µ | ]. PhD Thesis ν , protons on target 20 Preliminary reference Earth model 052019 (2015) [ hep-ex/1310.6677 ]. Recent Atmospheric Neutrino Results from Super-Kamiokande Limits on sterile neutrino mixing using atmospheric neutrinos in . 10 × Astropart. Phys. D91 , 6 . 6 A Combined A Fast Algorithm for Muon Track Reconstruction and its Application to the Search for sterile neutrino mixing using three years of IceCube DeepCore Searches for Sterile Neutrinos with the IceCube Detector Comput. Phys. Commun. Combined Analysis of (4) 297-356 (1981). hep-ex/1207.4809v2 , Measurement of the neutrino mixing angle , Phys. Rev. Measurements of neutrino oscillation in appearance and disappearance channels 1-13 (2006). 25 Atmospheric MUons from PArametric formulas: a fast GEnerator for neutrino , A Parameterisation of single and multiple muons in the deep water or ice 345-352 (2014) [ International Conference on Interconnection between Particle Physics and Neutrino masses and mixings: Status of known and unknown 3 25 A three-dimensional calculation of atmospheric neutrinos hep-ex/1605.01990v2 hep-ex/1701.05891 th 7 XVII International Workshop on Neutrino Telescopes 1604 , Neutrinos from the Milky Way astro-ph/0403630v1 hep-ex/1702.05160v1 , Astropart. Phys. 071801 (2016) [ by the T2K experiment with Planetary Interiors Using Accelerator and Atmospheric Neutrinos 151802 (2017) [ proceeding of MiniBooNE Excesses Super-Kamiokande (2004) [ Cosmology data Invited contribution prepared for the Nuclearcelebrating Physics the B Nobel Special Prize Issue in on Physics Neutrino 2015 Oscillations ANTARES Neutrino Telescope telescopes (MUPAGE) [5] http:://www.icrr.u-tokyo.ac.jp/ mhonda/nflx2014/index.html [6] G. Carminati et al., [8] http:://antares.in2p3.fr. [9] ANTARES Collaboration, [7] Y. Becherini et al., [15] T2K Collaboration, [16] A. Terliuk, at [17] Super-Kamiokande Collaboration, [13] MINOS Collaboration, [20] Super-Kamiokande Collaboration, [22] IceCube Collaboration, [12] A. M. Dziewonski, D. L. Anderson, [14] NOvA Collaboration, [18] MiniBooNE Collaboration, [19] IceCube Collaboration, [21] G.D. Barr at al., [11] F. Capozzi et al., ANTARES Atmospheric Neutrino Oscillations [10] E. Visser,