Baryon Destruction by Asymmetric Dark Matter

TL;DR

The paper investigates hylogenesis, a class of asymmetric dark matter models where DM carries antibaryon number and can destroy visible baryons via induced nucleon decay (IND). It develops the neutron-portal transfer operator L_eff ~ (1/Lambda^3) u_R^i d_R^j d_R^k Psi_R Phi + h.c. and shows that IND can yield an effective nucleon lifetime of order 10^{29}–10^{32} years when Lambda_IND sits near the weak scale, with GeV-scale mesons in the final state. IND signatures are explored across terrestrial nucleon-decay searches, collider monojet channels, and stellar environments, including neutron stars and white dwarfs; current bounds from nucleon decay experiments do not automatically exclude IND parameter space, while collider searches can reach Lambda_IND at the TeV scale. The work demonstrates a multi-pronged strategy to probe hylogenesis, linking cosmology, particle physics, and astrophysics, with potential observable consequences in upcoming experiments and observations.

Abstract

We investigate new and unusual signals that arise in theories where dark matter is asymmetric and carries a net antibaryon number, as may occur when the dark matter abundance is linked to the baryon abundance. Antibaryonic dark matter can cause {\it induced nucleon decay} by annihilating visible baryons through inelastic scattering. These processes lead to an effective nucleon lifetime of 10^{29}-10^{32} years in terrestrial nucleon decay experiments, if baryon number transfer between visible and dark sectors arises through new physics at the weak scale. The possibility of induced nucleon decay motivates a novel approach for direct detection of cosmic dark matter in nucleon decay experiments. Monojet searches (and related signatures) at hadron colliders also provide a complementary probe of weak-scale dark-matter--induced baryon number violation. Finally, we discuss the effects of baryon-destroying dark matter on stellar systems and show that it can be consistent with existing observations.

Figures (6)

• Figure 1: Feynman diagrams for induced nucleon decay. Box denotes IND vertex from Eq. \ref{['eq:Leff']}. Circle denotes strong interaction vertex given by $\mathscr{L}_0$ in Ref. Claudson:1981gh.
• Figure 2: Induced nucleon decay cross sections $(\sigma v)_{IND}$ for $p,n \to \pi^+,\pi^0$ (left) and $n \to \eta$ (right) as a function of fermion DM mass $m_{\Psi}$ for $|c_1| =\textrm{TeV}^{-3}$. Dotted (dashed) lines denote $N \Phi \to \bar{\Psi} M$ ($N \Psi \to \Phi^\dagger M$). Solid lines denote total rates $N \Phi \to \bar{\Psi} M$ + $N \Psi \to \Phi^\dagger M$. $(\sigma v)_{IND} = 10^{-39}$ cm$^3$/s corresponds to lifetime $\tau_N^{IND} = 10^{32}$ years.
• Figure 3: Induced nucleon decay cross sections $(\sigma v)_{IND}$ for $p \to K^+$ (left) and $n \to K^0$ (right) as a function of fermion DM mass $m_{\Psi}$ for $|c_{2,3}| =\textrm{TeV}^{-3}$. Dotted (dashed) lines denote $N \Phi \to \bar{\Psi} K$ ($N \Psi \to \Phi^\dagger K$) from operators $O_{2,3}$. Solid lines denote total rates $N \Phi \to \bar{\Psi} K$ + $N \Psi \to \Phi^\dagger K$. Grey regions show where existing nucleon decay bounds apply, described in text.
• Figure 4: Leading-order monojet production cross sections at the Tevatron subject to the cuts described in the text. We show lines for $m_X = 0.7\,5M,\,1.50\,M$ and $\Gamma = M/5,\,M/50$, and we set $\lambda = 1$ and $\zeta = 0.7$.
• Figure 5: Jet plus missing energy production cross sections at the LHC ($14\,\, {\rm TeV}$) subject to the cuts described in the text. We show lines for $m_X = 0.75\,M,\,1.50\,M$ and $\Gamma = M/5,\,M/50$, and we set $\lambda = 1$ and $\zeta = 0.7$.