Particle Physics with Neutrons at the ESS

Geovetenskaps hus (room:Högbomsalen), Stockholm University

Geovetenskaps hus (room:Högbomsalen), Stockholm University



Presently under construction, the European Spallation Source (ESS) will be the world's most powerful neutron source. This Nordita workshop which will take place in Stockholm will study the capability of the ESS to develop a unique program of experimental particle physics at the intensity and precision frontiers. Experiments at the ESS can address central open questions in modern physics such as the mechanism of baryogenesis, the strong CP problem, and the nature of dark matter. The experiments have sensitivity to particles and processes beyond the Standard Model at mass scales beyond that available at colliders.

All covered topics will be studied in the context of studying the technical potential of the ESS, the optimization of signatures and experimental search strategies, and the complementarity with the existing and planned collider and non-collider programs. In addition, there will be a dedicated day for the NNBAR experiment which is focused on the first two items below.
  • Neutron-antineutron oscillations Neutron-antineutron oscillations are the only experimentally clean probe of processes in which baryon number is the only hitherto conserved quantity to be violated. They feature in models of baryogenesis and physics beyond the Standard Model. Via the common violation of B-L and their appearance in various unification models, there exists a symbiosis between neutron-antineutron conversion, violating baryon number by two units, and neutrinoless double beta-decay, violating lepton number by two units. The former (latter) addresses the origin of the baryon asymmetry of universe (origin of neutrino mass).
  • Neutron- mirror neutron oscillations
  • Mirror particles are predicted in models which restore parity symmetry to the SM. The existence of such a dark sector of particles can explain dark matter. Mirror baryons as dark matter can be probed via several cosmological tests and also via direct detection with different portals. Mirror neutrinos can be natural candidates for sterile neutrinos, and the electrically neutral neutron offers one of other portals to the dark sector which violate baryon number by one unit.
  • Neutron decay correlations
  • The distribution of the decay products in space and energy can be parameterized by correlation coefficients. Neutron decays can be parameterised by correlation coefficients. Precision measurements can study a range of observables sensitive to these parameters. Physics beyond the SM predicts additional interactions, such as V+A, scalar or tensor interactions. The theoretical framework only assumes Lorentz invariance but no specific properties of the new physics. Therefore, neutron beta decay is a “broad band” probe for physics beyond the SM.
  • Neutron electric dipole moment
  • Searches for a non-zero neutron electric dipole moment (nEDM) are a critical component of the worldwide experimental particle physics program. Searches address the strong CP problem and are highly sensitive to new physics processes in which CP-violation occurs.
  • Hadronic parity violation
  • Intra-nucleon parity-violating interactions arise from an interplay of strong and weak interactions between quarks. The short range of the weak force allows a unique insight into the strong dynamics and thus quark confinement. The weak component of the nuclear force in systems of a few nucleons can be probed via neutron scattering.

  • Organising committee
  • David Milstead (Stockholms Universitet, co-chair)
  • Anca Tureanu (University of Helsinki, co-chair)
  • Gilles Ban (Caen)
  • Zurab Berezhiani (Univ. L'Aquila and LNGS/INFN)
  • Gustaaf Brooijmans (Columbia University)
  • Chris Crawford (University of Kentucky)
  • Gabriele Ferretti (Chalmers University)
  • Martín González-Alonso (CERN)
  • Yuri Kamyshkov (Tenneseee University)
  • Valentina Santoro (European Spallation Source)
  • Mike Snow (Indiana University)
  • Torsten Soldner (Institut Laue Langevin)
  • Albert Young (North Carolina State University)
Contribution list
    • Registration
    • Introduction and welcome
      • 1
        Welcome from Nordita
      • 2
        Welcome and practical details
      • 3
        The ANNI instrument
        Speaker: Torsten Soldner (ILL)
      • 4
        The HIBEAM experiment
        Speaker: Prof. David Milstead (Fysikum, SU)
      • 5
        How far can we get with in-beam UCN production at the ESS?
        Speaker: Oliver Zimmer (ILL)
    • 11:00 AM
    • The European Spallation Source
      • 6
        Status of the ESS
        Speaker: Shane Kennedy
      • 7
        Q&A ESS
    • 12:15 PM
    • nEDM
      • 8
        Neutron EDM: * Why we want to measure it * Why is it so difficult
        Speaker: Guillaume Pignol (LPSC)
      • 9
        nEDM at the SNS
        Speaker: Christopher Swank
      • 10
        The Neutron Beam EDM Experiment at ESS
        Speaker: Florian Piegsa
      • 11
        Status of the TUCAN EDM experiment
        Speaker: R Picker
      • 3:20 PM
      • 12
        Search for a neutron EDM at PSI
        Speaker: Philipp Schmidt Wellenburg
      • 13
        Neutron EDM searches at the ILL: present and future
        Speaker: Skyler Degenkolb (ILL)
      • 14
        Strategies for a cryogenic neutron EDM measurement
        Speaker: Clark Griffith
      • 15
        nEDM experiment at LANL
        Speaker: Takeyashu Ito
    • Mirror neutrons (1) -- Chair Yuri Kamyshkov
      Conveners: Prof. Yuri Kamyshkov (U. Tennessee) , Prof. Zurab Berezhiani (University L'Aquila and LNGS)
      • 16
        A. Serebrov (PNPI, NRC KI) Neutron Lifetime and Sterile Oscillations
        Speaker: Prof. Anatoly Serebrov (NRC “KI” Petersburg Nuclear Physics Institute, Gatchinа, Russia)
      • 17
        Z. Berezhiani (L'Aquila and LNGS) The nn' oscillations and neutron lifetime
        Speaker: Prof. Zurab Berezhiani (University L'Aquila and LNGS)
      • 10:30 AM
        Coffee Break 20'

        Coffee Break

      • 18
        Prof. Kenji MISHIMA (KEK) Neutron Lifetime by Appearance
        Speaker: Prof. Kenji MISHIMA (KEK)
      • 19
        Z. Tang (LANL) Proposed UCNProbe Experiment to Measure Branching n->p/n-> all
        Speaker: Dr Zhaowen Tang (LANL)
      • 20
        Discussion 30'
        Discussion 30'
    • 12:30 PM
    • Hadronic Parity violation
      • 21
        Parity odd and time reversal odd NN interactions
        Speaker: Gudkov Vladimir (South Carolina)
      • 22
        Nonleptonic weak interactions in NN and few nucleon systems
        Speaker: Vivani Michelle (INFN)
      • 23
        Lattice gauge theory calculations of NN weak amplitudes
        Speaker: Juelich Evan Berkowitz
      • 24
        Parity Violation in Lambda Nonleptonic Weak Decays
        Speaker: Dr Andrzej KUPSC (Uppsala University)
      • 3:20 PM
      • 25
        Results from the NPDGamma n-p weak interaction experiment at SNS
        Speaker: Libertad BARRóN-PALOS
      • 26
        Present status of the NN weak interaction and recent results
        Speaker: Jason Fry (Virginia)
      • 27
        NN weak interaction experiment opportunities at the ESS
        Speaker: Chris Crawford (Kentucky Uni.)
    • 28
      Speaker: Prof. Tord Ekelöf (Uppsala universitet)
    • Mirror neutrons (2) -- Chair Zurab Berezhiani
      Conveners: Prof. Yuri Kamyshkov (U. Tennessee) , Prof. Zurab Berezhiani (University L'Aquila and LNGS)
      • 29
        Ricardo Biondi (U. L'Aquila and LNGS) Analysis of nn' Experiments at ILL/Grenoble
        Speaker: Dr Ricardo Biondi (U. L'Aquila and LNGS)
      • 30
        Klaus Kirch (PSI, ETH) Analysis of Current nn' Search Experiment at PSI
        Speaker: Prof. Klaus Kirch (ETH, Zurich and PSI)
      • 31
        Albert Young (NCSU) Search for nn' by spin precession
        Speaker: Prof. Albert Young Young (North Carolina State University)
      • 10:30 AM
        Coffee Break 20'
      • 32
        Yuri Kamyshkov (U. Tennessee) Neutron Transition Magnetic Moment and nn' Oscillations
        Speaker: Prof. Yuri Kamyshkov (University of Tennessee)
      • 34
        Joshua Barrow (U. Tennessee) Sensitivity of HBEAM at ESS/ANNI to nn' search
        Speaker: Mr Joshua Barrow (University of Tennessee)
      • 35
        Discussion 10'
        Discussion 10'
    • 12:30 PM
    • Neutron-antineutrons oscillations (1)
      • 36
        Neutron-antineutron oscillations in nuclei
        Speaker: Jean Marc Richard (Institut de Physique Nucleaire & University of Lyon)
      • 37
        Effective Operators and Neutron-Antineutron Oscillations Versus Nuclear Instability
        Speaker: Akady Vainshtein
      • 38
        Processes that break baryon number by two units and their implications
        Speaker: Susan Gardner (University of Kentucky)
      • 39
        HIBEAM/nnbar backgrounds
        Speaker: Bernhard Meirose (Lund University)
      • 3:40 PM
      • 40
        A new operating mode in experiments searching for free neutron-antineutron oscillations based on coherent neutron and antineutron mirror reflections
        Speaker: Valery Nesvizhevsky (ILL)
      • 41
        nnbar discussion/plans
        Speaker: Albert Young
    • Workshop Dinner
    • Neutron-antineutrons oscillations (2)
      • 42
        UCN facility at VVRM
        Speaker: A. Serebrov
      • 43
        Lattice calculations for nnbar
        Speaker: Enrico Rinaldi
      • 44
        Project of an experiment to search for neutron-antineutron oscillations at reactor WWR-M
        Speaker: Alexey Fomin (PNPI NRC KI)
      • 45
        nnbar and dinucleon decay at DUNE
        Speaker: Yeon-jae Jwa
      • 10:30 AM
    • Precision neutron decay (1)
      • 46
        New Physics effects in neutron beta decay: a theory view
        Speaker: Martin Gonzales-Alonso
      • 47
        Precise theory predictions in neutron decay
        Speaker: Dr Andrzej Czarnecki
      • 48
        Precise theory predictions in neutron beta decay: current limitations and challenges
        I review recent progress in calculating the hadron structure-dependent radiative corrections to the neutron beta-decay. An application of dispersion relations to the $\gamma W$-box allowed to provide a data-driven estimate of the uncertainty of this calculation, reducing the hadronic uncertainty by almost a factor 2.
        Speaker: Dr Mikhail Gorshteyn
      • 49
        First-principles lattice QCD calculations of the neutron beta decay: challenges and prospects
        Measurements of the neutron lifetime and CKM matrix elements have evolved to become high-precisions tests of the existence of new physics. Thanks to the Standard Model relation between the neutron lifetime, the axial coupling $g_A$ of the neutron, and the CKM matrix element $V_{ud}$, we can use a QCD calculation of $g_A$ and $V_{ud}$ to learn about neutron decay from first-principles. Lattice QCD provides a robust framework to numerically compute inherently non-perturbative quantities from first principles. Starting only from the Lagrangian of QCD and owing to new improved numerical algorithms, we calculate the axial coupling of the neutron with unprecedented precision and thus obtain input about the neutron lifetime. This calculation is challenging and the outcome is very promising: it paves the way to understanding nuclear observables directly from QCD degrees of freedom with high accuracy.
        Speaker: Dr Enrico Rinaldi
    • 12:40 PM
    • Precision neutron decay (2)
      • 50
        UCNtau and prospects of neutron lifetime measurements
        Speaker: Dr Robert Pattie
      • 51
        An attempt to discuss the ''ultimate'' determination of correlation coefficients in neutron beta decay
        Speaker: Dr Stefan Baessler
      • 52
        Measurements of correlation coefficients with electron tracking and electron spin determination
        Speaker: Dr Kazimierz Bodek
      • 3:45 PM
      • 53
        Magnet concept for measurements of neutron decay correlations at the ESS
        Speaker: Dr Bastian Märkisch
      • 54
        Cyclotron radiation spectroscopy for neutron decay
        Speaker: Dr Brent VanDevender
    • Neutrons in cosmology
      Conveners: Prof. Yuri Kamyshkov (U. Tennessee) , Prof. Zurab Berezhiani (University L'Aquila and LNGS)
      • 55
        Shmuel Nussinov (Tel Aviv U.) Clustering of Dark Matter
        Speaker: Prof. Shmuel Nussinov (Tel Aviv University)
      • 56
        Pierluigi Belli (INFN, Rome II) New Results of DM Search with MM as a Possible Candidate
        Speaker: Prof. Pierluigi BELLI (INFN Sezione Roma Tor Vergata)
      • 57
        Massimo Mannarelli (LNGS) nn' Conversion and Neutron Stars
        Speaker: Prof. Massimo Mannarelli (INFN-LNGS)
      • 10:30 AM
        Coffee Break 20'
      • 58
        Zurab Berezhiani (for Fabrizio Nesti, U. L'Aquila and LNGS) DM Distribution in Galaxies - Does It Limit MM?
        Speaker: Prof. Zurab Berezhiani (L’Aquila and LNGS)
      • 59
        Torsten Bringmann (U. Oslo) Cogenesis from Neutron-Dark Matter Oscillations
        Speaker: Prof. Torsten Bringmann (University Oslo)
      • 60
        Christophe Grojean (DESY and Humboldt U.) Implications of an Improved Neutron-Antineutron Oscillation Search for Baryogenesis: A Minimal Effective Theory Analysis
        Speaker: Prof. Christophe Grojean (DESY and Humboldt Uni.)
    • 61
      The ESS in the future HEP landscape
      Speaker: Dr Adam Falkowski