Theoretical Innovations for Future Experiments Regarding Baryon Number Violation, Part 1

US/Eastern
Jordy de Vries (UMass), Joshua Barrow (The University of Tennessee), Leah Broussard (Oak Ridge National Laboratory), Michael Wagman (MIT)
Description

Theoretical Innovations for Future Experiments Regarding Baryon Number Violation, Part 1
Formerly Prospects for Baryon Number Violation by Two Units
An Amherst Center for Fundamental Interactions Workshop
In coordination with Snowmass 2021 Rare Processes and Precision Measurements Frontier: Topical Group on Baryon & Lepton Number Violation
(RP4)

This workshop is open for all to attend! Please join us from 10am-2pm EDT, and feel free to register! We will also be operating an optional Snowmass LOI/Contributed Paper writing session everyday of the workshop, typically from 2pm-3pm.

Abstract submission will be limited to previously agreed participants in light of postponed plans and time limits. We look forward to all of your contributions, participation, and attendance!
 

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The overarching topic of the workshop is the violation of Baryon-minus-Lepton ($ \mathcal{B} - \mathcal{L} $) number. $ \mathcal{B} - \mathcal{L} $ number is exactly conserved in the Standard Model, but the observed matter-antimatter asymmetry of the universe hints that beyond the Standard Model $ \mathcal{B} - \mathcal{L} $ violating processes could exist. Proton decay (PDK) experiments set very strong limits on $ \mathcal{B} $-violating interactions (though most conserve $ \mathcal{B} - \mathcal{L} $), pointing towards very high-energy scales around $10^{13}\,$TeV; however, models exist where the proton is stable while $ \mathcal{B} $ is still not a good symmetry (for instance, if $ \mathcal{B} $ is only violated by two units, i.e. $\Delta\mathcal{B}=2$). Such models lead to unique and powerful experimental signatures such as the transformations of neutrons into antineutrons ($n\rightarrow\bar{n}$, similar to kaon-antikaon oscillations due to strangeness-changing weak interactions) or decays of otherwise stable nuclei via dinucleon annihilation.

Recent years have seen significant theoretical developments of various aspects of these intriguing scenarios, and models have been created that naturally avoid PDK limits while solving other problems within the Standard Model such as the matter-antimatter asymmetry of the universe. Lattice-QCD calculations have made tremendous improvements in calculating QCD matrix elements that connect $\mathcal{B}$-violating quark interactions to observables. Studies in effective field theories for B-violating nuclear interactions have been initiated and applied to light nuclei, while novel intranuclear simulations have been developed to assess whether dinucleon decay processes can be separated from background in medium-heavy nuclei. At the same time, the prospects for future experiments look good: The European Spallation Source, DUNE, PNPI Gatchina, and Hyper-Kamiokande are all expected to attain significantly increased sensitivities to $ \mathcal{B} - \mathcal{L} $ violation.

Despite these recent exciting developments, the collective particle, lattice-QCD, nuclear, and experimental communities are currently rather disjoint and do not meet very often (if at all) to discuss strategy and theoretical necessities for mutualistic progress in the field. A major goal of this workshop is to bring together representatives across these communities to discuss what major challenges exist, what the prospects are for discovering $\Delta\mathcal{B}=2$ violation in future experiments, and the interpretation of experimental signals or limits in the broader context of $ \mathcal{B} - \mathcal{L} $ violation.

Furthermore, the US particle physics community is preparing to identify and rank scientific priorities with the goal of shaping the physics program for the next few decades as part of the Snowmass process, which will initiate in the next year. A summertime workshop frame ensures that we can better serve the experimental community interested in BNV by surveying the opportunities in experiment and theory in order to build the foundation for the strategy for Snowmass. This will allow for in-depth planning for both topics and convener strategies in order to be noticed within the broader field.

Co-organizers:
Joshua Barrow (University of Tennessee)--email for Indico questions
Leah Broussard (Oak Ridge National Laboratory)
Jordy de Vries (University of Massachusetts Amherst/Riken Brookhaven)--email for ACFI questions
Michael Wagman (Fermi National Accelerator Laboratory)

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Snowmass 2021 Letters of Interest for collective iteration by Workshop attendees:
ACFI Synthesis of Field 
DUNE $\mathcal{B-L}$ Violation
ESS NNBAR at the Large Beamport
ORNL to ESS $n\rightarrow n'$ and $n\rightarrow n' \rightarrow \bar{n}$ Searches

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Workshop Recordings
Day 1: Morning, Afternoon
Day 2: Morning, Afternoon
Day 3
Day 4

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Official Workshop Website
Previous Workshop Website (postponed due to COVID-19)

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Registration
Registration for the ACFI Theoretical Innovations for Future Experiments Regarding Baryon Number Violation by Two Units, Part I--A Snowmass Official Workshop
Participants
  • Albert Young
  • Alexey Fomin
  • Anca Tureanu
  • Bhupal Dev
  • Bingwei Long
  • Elena Golubeva
  • Georgia Karagiorgi
  • James Wells
  • Jean-Marc Richard
  • Jordy de Vries
  • Joshua Barrow
  • Julian Heeck
  • K.S. Babu
  • Leah Broussard
  • Linyan WAN
  • Maury Goodman
  • Pavel Fileviez Perez
  • Prajwal Mohan Murthy
  • Praveen Kumar
  • Rabindra Mohapatra
  • Robert Shrock
  • Rukmani Mohanta
  • Sudhakantha Girmohanta
  • Susan Gardner
  • Sze Chun Yiu
  • Valentina Santoro
  • Zurab Berezhiani
    • 1
      Overview of some recent theoretical developments in neutron oscillation

      There are a number of puzzles of beyond the standard model physics that can be probed directly by the process of neutron-anti-neutron oscillation in contrast with the othetr popular baryon violating process i.e. the typical GUT motivated proton decay mode $p\rightarrow e^+ π^0$. The most important of them is a direct understanding of the baryon asymmetry of the universe on which the typical GUT motivated baryon violation cannot. Also if neutron oscillation is observable, leptogenesis mechanism also does not work. The mechanism for such baryogenesis is the post sphaleron model which implemented in the context of $SU(2)_L \times SU(2)_R \times SU(4)_C$ model for neutron oscillation leads to an upper limit on neutron-antineutron oscillation time within the reach of currently proposed experiments. Furthermore, if neutrino-less double beta decay fails to yield a positive signal, an alternative way to establish that lepton number is violated and neutrinos are their own antiparticles is to discover both proton decay and neutron oscillations. Also the belief that neutrinos are likely to be Majorana fermions strongly suggests that there may be a small Majorana component to the neutron mass which leads to neutron oscillation. All these arguments provide strong arguments for a new search for neutron-anti-neutron oscillation. In the second part of the talk, I point out some constraints arising from big bang nucleosynthesis that suppress the neutron mirror neutron oscillation which is under study in several experiments.

      Speaker: Rabindra Mohapatra (University of Maryland, College Park, USA)
    • 2
      Some Recent Results on Models with $n-\bar n$ Oscillations

      We discuss models that can feature $n-\bar n$ oscillations at observable
      levels. These are extra-dimensional theories with Standard-Model fermions
      propagating in the extra dimensions. Interestingly, while proton decay can
      be suppressed well below experimental limits in these models, $n-\bar n$
      oscillations can occur at levels comparable to current limits. Thus,
      in these theories, $n-\bar n$ oscillations and the associated $\Delta B=-2$
      dinucleon decays can be the dominant manfestation of baryon-number violation.
      Analyses are given within the context of a Standard-Model effective field
      theory and a theory involving a left-right symmetry group.

      Speaker: Prof. Robert Shrock
    • 11:00 AM
      Coffee Break, Discussion

      Check out the Zoom Coffee Room

    • 3
      The European Spallation Source and Future Free Neutron Oscillations Searches

      The European Spallation Source ESS, presently under construction, in Lund, Sweden, is a multi-disciplinary international laboratory. It will operate the world's most powerful pulsed neutron source. Taking advantage of the unique potential of the ESS, the NNBAR collaboration proposed a two-stage program of experiments to perform high precision searches for neutron conversion in a range of baryon number violation (BNV) channels culminating in an ultimate sensitivity increase for $n\rightarrow\bar{n}$ oscillations of three orders of magnitude over the previously attained limit obtained at the Institut Laue-Langevin ILL.
      The first stage of this program HIBEAM (High Intensity Baryon Extraction and Measurement) will employ the fundamental physics beamline during the first phase of the ESS operation. This stage focuses principally on searches for neutron conversion to sterile neutrons n'. The second stage, NNBAR will exploit the Large Beam Port (LBP), a unique component of the ESS facility to search directly for $n\rightarrow\bar{n}$.
      In the talk, I will briefly discuss the scientific motivations for these searches, the status of the the European Spallation Source and the recent developments in the HIBEAM/NNBAR
      Collaboration.

      Speaker: Valentina Santoro (ESS)
    • 12:00 PM
      Lunch Break, Discussion

      Check out the Zoom Lunch Room

    • 4
      Neutron-antineutron oscillation search at Super-Kamiokande

      As a baryon number violating process with $\Delta B = \Delta (B−L) = 2$, neutron-antineutron oscillation ($n\to\bar n$)provides an important candidate and a unique probe to the baryon asymmetry. We performed a search for $n\to\bar n$ oscillation with the Super-Kamiokande (SK) experiment. Full exposure data set of SK was analyzed using a multi-variate analysis based on kinematic variables and basic distributions from simulated $n\to\bar n$ signal events and atmospheric neutrino backgrounds. We observed 11 events, compared with the expected number of background events 9.3. The upper limit of nuclear lifetime is calculated as $3.6×10^{32}$ years at 90% CL, significantly improved from the present best-limit $1.9×10^{32}$ years of SK-I.

      Speaker: Linyan WAN (Boston University)
    • 5
      Search for $n\rightarrow\bar{n}$ in the Deep Underground Neutrino Experiment

      The Deep Underground Neutrino Experiment (DUNE) utilizes Liquid Argon Time Projection Chamber (LArTPC) technology to deeply probe $\nu$ and beyond Standard Model (BSM) interactions with great granularity. The DUNE Technical Design Report (TDR) prioritizes BSM searches for baryon number violation (BNV) modes such as proton decay and neutron-antineutron transformation ($n\rightarrow\bar{n}$), showing expected lower limit targets for DUNE. The previous DUNE analysis techniques used for DUNE's $n\rightarrow\bar{n}$ target will be highlighted, as well as ongoing studies utilizing similar procedures which move toward understanding intranuclear modeling systematics related to this unknown rare process.

      Speaker: Joshua Barrow (The University of Tennessee)
    • 6
      Possible Use Of Neutron Optics for Optimization of a Free Neutron-Antineutron Oscillation Search

      Neutron-antineutron oscillations can survive sufficiently coherent interactions with matter and external fields without suppressing the oscillation rate. I describe some examples of this phenomenon which might find practical applications
      in the design of future experiments.

      Speaker: William Snow (Indiana University)
    • Snowmass LOI/Contributed (White)Paper Writing
    • 7
      Baryon-number violation by two units in chiral effective field theory

      I discuss a framework based on chiral effective filed theory for treating baryon-number violation by two units in nuclei. The deuteron lifetime is used as an application to illustrate this framework. The emphasis is given to how a consistent power counting is built and what statements can be drawn out of it.

      Speaker: Bingwei Long
    • 8
      Calculation of the Suppression Factor for Bound Neutron-Antineutron Transformation

      I review and revisit the calculation of the lifetime of nuclei due to neutron-antineutron oscillations.
      It is stressed that the oscillation and the subsequent annihilation take place mainly outside the nucleus and thus hardly suffer from drastic renormalization due to the nuclear medium. The ingredients of the calculation can be safely extracted from nuclear shell-model wave-functions, and optical models fitting the low-energy data on antinucleon-nucleus interaction. The main result is that the lifetime of a nucleus behaves as $T=T_R\,\tau_{n\bar n}^2$, with a factor $T_R$, often referred to as reduced lifetime or suppression factor of about $10^{22-23}\,$s$^{-1}$. A remarkable feature is that $T_R$ is stable against variations of the antinucleon-nucleus potential.

      Speaker: Jean-Marc Richard (IP2I,, IN2P3, U. of Lyon)
    • 11:00 AM
      Coffee Break, Discussion

      Check out the Zoom Coffee Room

    • Discussions

      Tuesday Discussion: Differences in Intranuclear Suppression Factors: Why? How is it important?
      Jean-Marc Richard, Bingwei Long

      The following questions are often raised when discussing the neutron-antineutron oscillations nuclei:

      How well is known the nucleon-antinucleon interaction?
      How well is known the antinucleon-nucleus interaction?
      Is the shell model an appropriate tool?
      How comes that the neutron-antineutron oscillation takes place mainly at the surface of the nucleus?
      What type of final state is expected for antineutron-nucleus annihilation arising from neutron oscillation?
      The above issues, and others, will be adressed during the discussion session.


      Thursday Discussion: Snowmass Strategies: Past and Present

      Albert Young, Bhupal Dev, Georgia Karagiorgi, Gustaaf Brooijmans, Joshua Barrow, K.S. Babu, Leah Broussard, Yuri Kamyshkov


      • 9
        Differences in Intranuclear Suppression Factors: Why? How is it important?

        The following questions are often raised when discussing the neutron-antineutron oscillations nuclei:

        • How well is known the nucleon-antinucleon interaction?
        • How well is known the antinucleon-nucleus interaction?
        • Is the shell model an appropriate tool?
        • How comes that the neutron-antineutron oscillation takes place mainly at the surface of the nucleus?
        • What type of final state is expected for antineutron-nucleus annihilation arising from neutron oscillation?

        The above issues, and others, will be adressed during the discussion session.

        Speakers: Jean-Marc Richard (IP2I,, IN2P3, U. of Lyon), Bingwei Long (Sichuan University)
    • 12:00 PM
      Lunch Break, Discussion

      Check out the Zoom Lunch Room

    • 10
      Lattice QCD matrix elements of Delta B = 2 operators

      Theories of B-L violation beyond the Standard Model (BSM) generically lead to the appearance of six-quark operators in Standard Model effective field theory that give rise to neutron-antineutron oscillations and Delta B = 2 nuclear decays. Reliably connecting the results of experimental searches for these processes to constraints on the parameters of BSM physics theories requires Standard Model calculations of the matrix elements of these six-quark operators between hadronic states. I will report on lattice quantum chromodyanmics calculations of a complete basis of Delta B = 2 six-quark operators and a few of their implications for current and future searches for Delta B = 2 processes.

      Speaker: Michael Wagman
    • 11
      Update on the post-sphaleron baryogenesis model prediction for neutron-antineutron oscillation time

      Post-sphaleron baryogenesis (PSB) is an attractive low-scale mechanism to explain the observed matter-antimatter asymmetry of the Universe. The same \Delta B=2 operator that gives rise to baryogenesis in this scenario also leads to neutron-antineutron oscillation. We show that the PSB mechanism, when embedded in a quark-lepton unified model based on the Pati-Salam gauge group, leads to an absolute upper limit on the neutron-antineutron oscillation time, which might be within reach of future experiments. The multi-TeV-scale scalar diquarks in this model could also be searched for at the LHC and future hadron colliders.

      Speakers: Bhupal Dev (University of Maryland), Bhupal Dev (University of Manchester/TUM)
    • 12
      Probing High Scale Theories with $n-\bar{n}$ Oscillations

      $n-\bar{n}$ oscillations can be used to probe theories at a high energy scale, such as grand unified theories. In this talk I will illustrate this with two examples. In the first example, $n-\bar{n}$ oscillation arises in a left-right symmetric model realized near the GUT scale that provides a solution to the strong CP problem. The $n-\bar{n}$ oscillation time is closely tied to neutrino masses, and is expected to be in the range of $10^8-10^{10}$ sec. In the second example, $SO(10)$ grand unified theory breaks to the standard model directly, but leaves behind a color sextet scalar field at the TeV scale. This scalar helps with unification of gauge couplings and leads to $n-\bar{n}$ oscillations, which is closely tied to baryon asymmetry generation. For typical values of the model parameters, $\tau_{n-\bar{n}} \sim 10^9 - 10^{10}$ sec. is obtained.

      Speakers: K.S. Babu (Oklahoma State University), Ks Babu (Oklahoma State)
    • Snowmass LOI/Contributed (White)Paper Writing
    • 13
      Neutron-antineutron oscillation improvements and baryogenesis

      Wherein I discuss how improvements on neutron-antineutron oscillations and its impact on a minimal theory of baryogenesis.

      Speaker: James Wells
    • 14
      Search for NNbar with UCN

      The scheme of the experiment on search for neutron-antineutron oscillations based on the storage of ultracold neutrons in a material trap is presented. The idea of such an experiment becomes important due to creation of new powerful UCN sources. The sensitivity of the experiment was obtained in Monte Carlo simulation of UCN transport and storage. It mostly depends on the trap size and the amount of UCN in it. Design of the setup, magnetic shielding study, neutron storage and annihilation detection simulations are presented. The possibilities of increasing the sensitivity of the experiment due to the accumulation of the antineutron phase in the collisions of neutrons with the walls are considered.

      Speaker: Alexey Fomin (NRC "Kurchatov Institute" - PNPI)
    • 11:00 AM
      Coffee Break, Discussion

      Check out the Zoom Coffee Room

    • 15
      New scenario for the neutron--antineutron oscillation: shortcut through mirror world

      Existing bounds on the neutron-antineutron mass mixing, $\epsilon_{n\bar n} < {\rm few} \times 10^{-24}$~eV, impose a severe upper limit on $n - \bar n$ transition probability, $P_{n\bar n}(t) < (t/0.1 ~{\rm s})^2 \times 10^{-18}$ or so, where $t$ is the neutron flight time. Here we propose a new mechanism of $n- \bar n$ transition which is not induced by direct mass mixing $\epsilon_{n\bar n}$ but is mediated instead by the neutron mass mixings $\epsilon_{nn'}$ and $\epsilon_{n\bar{n}'}$ with the hypothetical states of mirror neutron $n'$ and mirror antineutron $\bar{n}'$ which can be as large as $\sim 10^{-14}$~eV or so, without contradicting the present experimental limits and nuclear stability bounds. The probabilities of $n-n'$ and $n-\bar{n}'$ transitions, $P_{nn'}$ and $P_{n\bar{n}'}$, depend on environmental conditions in mirror sector, and by scanning over the magnetic field values in experiments they can be resonantly amplified. This opens up a possibility of $n-\bar n$ transition with the probability $P_{n\bar n} = P_{nn'} P_{n\bar{n}'}$ which can reach the values up to $\sim 10^{-8} $. For finding this effect in real experiments, the magnetic field should be suppressed but properly varied. This scenario points towards the scale of few TeV of new physics which can be responsible for these mixings, and can also suggest a new low scale co-baryogenesis mechanism between ordinary and mirror sectors.

      Speaker: Prof. Zurab Berezhiani (University of L'Aquila)
    • 12:00 PM
      Lunch Break, Discussion

      Check out the Zoom Lunch Room

    • 16
      Search for neutron oscillations to a sterile state ($ n \rightarrow n^{'} $) and to an antineutron ($ n \rightarrow \overline{n} $)

      As follows from theoretical conjectures of Z. Berezhiani et al. [2006-2020] the neutron that is part of the Standard Model ($SM$) can oscillate into sterile state $ n \rightarrow n^{'} $ , thus leading to neutron disappearance or baryon number violation $ \Delta B=-1 $. However, this can be only an apparent disappearance: if the sterile neutron $ n^{'}~ $ is part of the Mirror Standard Model ($ SM^{'} $) with corresponding mirror baryon number $ B^{'} $ the transformation $ n \rightarrow n^{'} $ can occur without violation of the global baryon number $ \Delta \left( B+B^{'} \right) =0 $. This process will be not necessarily suppressed by high mass scale and can have observable probability corresponding to oscillation times as small as 1-100 s. The $ SM^{'} $ sector is assumed to be an exact copy of $SM$ with the same particle content and the same gauge interactions within $ SM^{'} $, but these interactions are absent between $SM$ and $ SM^{'} $ particles, e.g. mirror photon $ \gamma^{'} $ will not interact with $SM$ charges and vice versa. The gravity however is a common interaction for both sectors thus making $ SM^{'} $ a good candidate for the Dark Matter. Also, additional new BSM interactions are conjectured that mix the neutral particles of $SM$ and $ SM^{'} $ sectors (like $ \gamma , \nu , n $ and possibly other neutral particles) that makes such interactions responsible for the direct detection of DM and for transformations like $ \gamma \rightarrow \gamma^{'},~ \nu \rightarrow \nu ^{'}~ $, and particularly interesting $ n \rightarrow n^{'} $, as a most convenient for experimental observation process.
      Existing neutron sources provide cold neutron beams with high intensities that can be used for rather simple and inexpensive experimental searches like $ n \rightarrow n^{'} $ disappearance, $ n \rightarrow n^{'} \rightarrow n $ regeneration, searches for neutron transition magnetic moment, and neutron – antineutron transformations through mirror-state oscillations $ n \rightarrow n^{'} \rightarrow \overline{n} $. Plans for such measurements with existing neutron sources at the Oak Ridge National Laboratory and at the future European Spallation Source and the sensitivity reach will be discussed in the workshop presentation.

      Speaker: Yuri Kamyshkov (University of Tennessee)
    • 17
      Neutrons at ORNL and ESS: A Synergistic Program

      Oak Ridge National Laboratory has some of the world’s most advanced neutron sources, the High Flux Isotope Reactor (HFIR) which is a continuous source of neutrons from nuclear fission, and the Spallation Neutron Source, a pulsed source created by an accelerated proton beam hitting a mercury target. Not only are both good sources for neutrons, they are also excellent neutrino sources with exceptional characteristics. An ambitious and growing fundamental neutron and neutrino science program is in operation at both the SNS and HFIR. Both facilities will undergo major upgrades. A Second Target Station will be built at the SNS, driven by a 2.8MW proton beam, and HFIR will be upgraded with a new pressure vessel and reflector. This provides a unique and timely opportunity to explore the opportunities these upgraded facilities offer for a compelling future fundamental physics program. The Physics Division invites the community to develop a strong synergistic program.

      Speakers: Marcel Demarteau (Oak Ridge National Laboratory), Marcel Demarteau (Argonne National Laboratory), Marcellinus Demarteau
    • Discussions

      Tuesday Discussion: Differences in Intranuclear Suppression Factors: Why? How is it important?
      Jean-Marc Richard, Bingwei Long

      The following questions are often raised when discussing the neutron-antineutron oscillations nuclei:

      How well is known the nucleon-antinucleon interaction?
      How well is known the antinucleon-nucleus interaction?
      Is the shell model an appropriate tool?
      How comes that the neutron-antineutron oscillation takes place mainly at the surface of the nucleus?
      What type of final state is expected for antineutron-nucleus annihilation arising from neutron oscillation?
      The above issues, and others, will be adressed during the discussion session.


      Thursday Discussion: Snowmass Strategies: Past and Present

      Albert Young, Bhupal Dev, Georgia Karagiorgi, Gustaaf Brooijmans, Joshua Barrow, K.S. Babu, Leah Broussard, Yuri Kamyshkov


      • 18
        (Suggested Discussion) Snowmass Strategies: Past and Present
        Speakers: Albert Young (North Carolina State University/Triangle Universities Nuclear Laboratory), Bhupal Dev (University of Manchester/TUM), Georgia Karagiorgi (Columbia University), Georgia Karagiorgi (Columbia University), Gustaaf Brooijmans (Columbia University), Joshua Barrow (The University of Tennessee), K.S. Babu (Oklahoma State University), Ks Babu (Oklahoma State), Leah Broussard (Oak Ridge National Laboratory), Yuri Kamyshkov (University of Tennessee)
    • Snowmass LOI/Contributed (White)Paper Writing
    • 19
      Searches for scalars that carry B or L, taken broadly: whither and wherefore

      In many models of new physics, the expected rate of processes that break
      baryon number by two units rests on the features of a poorly known
      scalar sector, whose members can carry B or L quantum numbers. Thus
      the BNV discovery prospects in these channels are controlled by the extent
      to which the associated scalars are excluded by experiments. Working
      in the context of minimal scalar models, I will survey and discuss
      the existing constraints and note what windows of opportunity remain for
      the discovery of light new scalars. With these, new experiments
      become tenable, and I emphasize the complementary of these
      to other ongoing efforts and their broader implications.

      Speaker: Susan Gardner (U Kentucky)
    • 20
      Covering baryon number violation with inclusive searches

      Baryon number violation is an extremely sensitive probe of physics beyond the Standard Model. However, the continued absence of any signals raises the question if we are actually looking in the right places or if we should broaden our search strategies. In this talk I will propose inclusive nucleon decay searches as a convenient method to cover a lot of parameter space, including sensitivity to new light particles and dark matter induced baryon number violation.

      Speaker: Julian Heeck (UC Irvine)
    • 11:00 AM
      Coffee Break, Discussion

      Check out the Zoom Coffee Room

    • 21
      Measurements of Neutron Coupling to a Mirror Sector Using Spin Precession

      Couplings between neutrons and a mirror sector can be formulated in terms of observable effects for precession-measurements (as has been pointed out by Berezhiani), bringing to bear the tools and experimental resources already in play for the measurement of static electric dipole moments.limits for measurements with the coupling strength for neutrons to mirror neutrons. Some details of measurements in an EDM-like geometry can be used to place limits on mirror couplings and provide information on the orientation and strength of a mirror magnetic field, should it exist in the mirror sector.

      Speaker: Prof. Albert Young (North Carolina State University/Triangle Universities Nuclear Laboratory)
    • 12:00 PM
      Lunch Break, Discussion

      Check out the Zoom Lunch Room

    • 22
      Exciting New Possibilities for Baryon Number Violation

      Proton decay can be sufficiently suppressed in an extra-dimensional model where Standard-Model (SM) fermions are localized at different points in the extra dimension(s), whereas $n$-$\bar n$ oscillations can occur at a rate comparable to the current observable limit. We show that in a left-right symmetric model with extra dimensions this effect is even more enhanced. Several nucleon and dinucleon decays to leptonic final states are considered in the extra-dimensional framework and found to be sufficiently suppressed. $n$-$\bar n$ oscillations are special in this extra-dimensional framework as separating quark and lepton wavefunctions in the extra dimensions to suppress nucleon and dinucleon decays to leptonic final states does not suppress $n$-$\bar n$ oscillations, which only involve quarks.

      Speaker: Mr Sudhakantha Girmohanta (Stony Brook University)
    • 23
      Perspectives on Baryon Number Violation

      In this talk I discuss baryon number violation and the relationship between processes that violate it by one or two units. While proton decay searches currently probe baryon number violation by one unit up to very high scales, those that violate it by two units can be directly motivated by the baryon asymmetry of the universe and can be the leading baryon number violating signal in some models. I will also describe some recent work involving new signatures of baryon number violation such as the decay of atomic hydrogen.

      Speaker: David McKeen (TRIUMF)
    • Snowmass LOI/Contributed (White)Paper Writing