Search for new physics with the SHiP experiment at cern Oliver - PowerPoint PPT Presentation

Search for new physics with the SHiP experiment at cern Oliver Lantwin on behalf of the SHiP Collaboration. [ oliver.lantwin@cern.ch ] eps-hep 2017 7th July 2017

2/16 Technical Proposal: [CERN-SPSC-2015-016] Introduction eps-hep 2017 Oliver Lantwin (Imperial College London) Physics Proposal: [CERN-SPSC-2015-017] ~250 scientific authors 17 member countries: Bulgaria, Chile, Denmark, France, Germany, Italy, Japan, Korea, Portugal, Russia, Serbia, Sweden, Switzerland, Turkey, United Kingdom, Ukraine, United States of America + CERN, DUBNA 49 member institutes: Sofia, Valparaiso, Niels Bohr Institute Copenhagen, LAL Orsay, LPNHE Paris, Berlin, Humboldt University Hamburg, Mainz, Bari, Bologna, Cagliari, Ferrara, Lab. Naz. Gran Sasso, Frascati, Naples, Rome, Aichi, Kobe, Nagoya, Nihon, Toho, Gyeongsang, LIP Coimbra, Dubna, ITEP Moscow, INR Moscow, P.N. Lebedev Physical Institute Moscow, Kurchatov Institute Moscow, IHEP Protvino, Petersburg Nuclear Physics Institute St. Petersburg, Moscow Engineering Physics Institute, Skobeltsyn Institute of Nuclear Physics Moscow, Yandex School of Data Analysis, Belgrado, Stockholm, Uppsala, CERN, Geneva, EPFL Lausanne, Zurich, Middle East Technical University Ankara, Ankara University, Imperial College London, University College London, Rutherford Appleton Laboratory, Bristol, Warwick, Taras Shevchenko National University Kyiv, Florida 5 associated institutes: Jeju, Gwangju, Chonnam, National University of Science and Technology "MISIS“ Moscow, St. Petersburg Polytechnic University

The state of particle physics “We know there is new physics,…” 1. Neutrino masses and their origin 2. Dark Matter 3. Baryon asymmetry of the universe weakly) Oliver Lantwin (Imperial College London) eps-hep 2017 Introduction 3/16 ◮ There is experimental evidence for new physics beyond the standard model (sm): → these problems could be solved by new particles that are coupled to the standard model (if very ◮ And of course there are plenty of theoretical criticisms of the standard model…

New physics? Energy scale Introduction eps-hep 2017 Oliver Lantwin (Imperial College London) “… We need to be as broad as possible in our exploratory approach” fcc lhc Energy Frontier Flavour physics Neutrino physics Hidden sector Intensity Frontier “… We don’t know where it is…” Interaction Strength Unknown Physics 4/16 ◮ We do not know at which energy new physics will show up. ◮ New physics could have eluded us so far in two ways: ◮ new physics is at a higher energy scale ◮ new physics is too weakly coupled to be detected at the current generation of experiments ◮ s c i s y ◮ h P n w o n K ◮ ◮ ◮ — Fabiola Gianotti I will focus on the second option: Super-weakly coupled new physics with m NP < O ( 10 GeV ) .

Hidden sectors & portals If there is super weakly coupled new physics, there generally is a portal that mediates between the Introduction eps-hep 2017 Oliver Lantwin (Imperial College London) See our physics proposal [CERN-SPSC-2015-017] for an overview of the many other models we can test! Consider example of the fermion portal here: hnl 5/16 There are four possible types of portal: standard model and one or more hidden particles, i.e. the hidden sector (hs): L = L SM + L portal + L HS ( H † H ) φ ◮ Scalar (e.g. dark scalar, dark Higgs) ǫF µν F ′ ◮ Vector (e.g. dark photon) µν H † NL ◮ Fermion (e.g. heavy neutral lepton (hnl)) aF µν ˜ F µν ◮ Axion-like particle (alp)

6/16 and sphaelerons can solve all of the experimental problems is the neutrino Introduction eps-hep 2017 Oliver Lantwin (Imperial College London) A model with a minimal number of additional particles that Example: Fermion portal/hnl of the ν msm minimal standard model ( ν msm) [arχiv:hep-ph/0505013] ◮ Add three right-handed Majorana neutrinos N i : ◮ Light N 1 with mass O ( 10 keV ) , essentially decoupled from N 2 , 3 ◮ Dark matter candidate ◮ Heavy N 2 , 3 with masses O ( 1 GeV ) , weakly coupled to standard model → hnl ◮ Set active neutrino masses ◮ Create baryon asymmetry of the universe via leptogenesis ◮ Produced in charm decays; detectable via visible decays: µ µ − c ν µ W + N 2 , 3 D + W + s ν µ d s π + N 2 , 3 u

Concept Target/Magnetised hadron absorber The SHiP experiment eps-hep 2017 Oliver Lantwin (Imperial College London) Generic signatures predicted by many new physics models 2. Via scattering in nuclear emulsion 1. Via decay to visible particles in hidden sector spectrometer Two signatures: 7/16 Decay volume Emulsion spectrometer* Active muon shield Hidden sector spectrometer Yields for 2 × 10 20 pot (5 years): > 10 18 D , > 10 16 τ π µ hnl V G e p 0 0 4 @ 115 m * see talk by Marilisa De Serio in the Neutrino Physics track

Crucial challenges Maximise intensity and mass reach new beam dump facility (bdf) in the North Area instead of fast extraction sps Oliver Lantwin (Imperial College London) eps-hep 2017 The SHiP experiment 8/16 ◮ Intense proton beam from the sps @400 GeV at the ◮ Very dense target of 12 × λ int ◮ abundant production of heavy fmavour ◮ reduced neutrino production from π and K decays ◮ Number of protons per cycle similar to cngs, but slow ◮ Operation in parallel with lhc, other beam-lines at the

Crucial challenges target at the h4 test-beam at cern’s sps is planned for The SHiP experiment eps-hep 2017 Oliver Lantwin (Imperial College London) [2017 JINST 12 P05011] Acceptance Zero background 2018 maximise the experimental acceptance The muon shield is the critical component to optimise to least 6 orders of magnitude 9/16 y [ m ] � � ◮ Passive hadron absorber ◮ Active muon shield that has to reduce muon fmux by at ◮ kinematic range of muons up to p ∼ 350 GeV ◮ kinematic range of muons up to p T ∼ 8 GeV ◮ A measurement of the muon spectrum for the SHiP z [ m ]

Crucial challenges pid to suppress background and distin- The SHiP experiment eps-hep 2017 Oliver Lantwin (Imperial College London) Aim for redundancy to suppress background Sgoldstino Axion portal, sgoldstino hnl, neutralino, axino Vector, scalar, axion portals; goldstino hnl, neutralino Background taggers for any visi- Particle guish signal fjnal states: Final states measurement teractions to negligible levels ble particles entering or exiting the decay vessel Zero background Evacuated decay vessel to reduce the background from neutrino in- impact parameter 10/16 combinatorial background from muons vertexing and ◮ Timing † to suppress ◮ Tracking for π µ hnl ℓ ± π ∓ , ℓ ± K ∓ , ℓ ± ρ ∓ ℓ ± ℓ ∓ ℓ ± ℓ ∓ ν ℓ γγ π 0 π 0 † see poster by Alexander Korzenev

Status 2013 2015 Now! European strategy meeting (espp) in 2019/2020 Oliver Lantwin (Imperial College London) eps-hep 2017 The SHiP experiment 11/16 ◮ Expression of interest ◮ Technical proposal (tp) & physics proposal (pp) ◮ spsc and cern research board recommended we continue to a comprehensive design study (cds) phase → Re-optimisation of the entire experiment ◮ Part of the cern Physics beyond colliders (pbc) working group and will be an input to the

Sensitivity: hnl model SHiP Sensitivity eps-hep 2017 Oliver Lantwin (Imperial College London) NB: Before re-optimisation Theoretical limits from: hierarchy. 12/16 ◮ Best sensitivity up to charm kinematic limit ◮ Signifjcant contribution from B -decays ◮ Baryon asymmetry of the universe (bau) ◮ Big bang nucleosynthesis (bbn) ◮ Model-independent limit for any Seesaw Figure: hnl sensitivity at SHiP for ν msm with U 2 e : U 2 µ : U 2 τ = 1 : 16 : 3 . 8 and a normal neutrino mass

Sensitivity: Dark Scalars Figure: Dark scalar sensitivity at SHiP. best complementing other experiments SHiP too short for SHiP and too long for NB: Before re-optimisation Oliver Lantwin (Imperial College London) eps-hep 2017 SHiP Sensitivity 13/16 ◮ For short lifetimes B -factories and LHCb ◮ SHiP covers unique parameter space ◮ Large contribution from B -decays at ◮ “Hole” at cτ ∼ O ( m ) , where lifetime is B -experiments

Sensitivity: Dark Photons Figure: Dark photon sensitivity at SHiP. SHiP Sensitivity eps-hep 2017 Oliver Lantwin (Imperial College London) NB: Before re-optimisation determined by short lifetime other experiments 14/16 Work in progress meson decays years ◮ Based on > 10 20 γ at SHiP over 5 ◮ Visible decays of dark photons ◮ Produced in qcd, bremsstrahlung and ◮ No production via em showers yet → ◮ Complementary to regions studied by ◮ Top-right edge of sensitivity

Sensitivity: Light Dark Matter nuclear recoil in nuclear emulsion: SHiP Sensitivity eps-hep 2017 Oliver Lantwin (Imperial College London) NB: Before re-optimisation ldmx@slac: for scattering kinematics can be exploited. 15/16 Two approaches: quickly lose sensitivity. “direct detection” experiments ◮ For dark matter lighter than wimps ◮ missing mass/energy searches ( ∝ U 2 ) ◮ scattering/recoil ( ∝ U 4 ) SHiP: Indirect detection via electron and ◮ Main background for electron recoil from ν e scattering, but differences in the ◮ Preliminary; cascade production not yet implemented → already best sensitivity Figure: Light dark matter sensitivity at SHiP for m A ′ m χ = 3 . ◮ missing energy at electron beam