Evidence for a stochastic gravitational wave (GW) background, plausibly originating from the merger of supermassive black holes (SMBHs), is accumulating with observations pulsar timing arrays. An outstanding question how inspiraling SMBHs get past “final parsec” separation, where they have tendency to stall before GW emission alone can make binary coalesce. We argue that dynamical friction dark matter (DM) spike surrounding sufficient resolve this puzzle, if DM has self-interaction cross...

Abstract Motivated by the recent evidence for $$B^+\rightarrow K^+\bar{\nu } \nu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>B</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>K</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> decays at Belle II, we point out that fully invisible $$B_d$$ <mml:msub> <mml:mi>d</mml:mi> </mml:msub> and $$B_s$$ <mml:mi>s</mml:mi> meson are strongly...

We determine the model-independent component of couplings axions to electroweak gauge bosons, induced by minimal coupling QCD inherent solving strong CP problem. The case invisible axion is developed first, and impact on $W$ $Z$ discussed. analysis extended next generic framework heavy true low scales, corresponding scenarios with enlarged confining sector. mass dependence photons, bosons determined. Furthermore, we perform a two-coupling-at-a-time phenomenological study where gluonic...

The low-energy electronic recoil spectrum in XENON1T provides an intriguing hint for potential new physics. At the same time, observations of horizontal branch stars favor existence a small amount extra cooling compared to one expected from Standard Model particle content. In this note, we argue that hidden photon with mass ∼ 2.5 keV and kinetic mixing 10−15 allows good fit both these excesses. scenario, signal detected is due absorption dark matter particles, whereas anomalous arises...

Dark sector particles at the GeV scale carrying baryon number provide an attractive framework for understanding origin of dark matter and matter-antimatter asymmetry universe. We demonstrate that decays hadronic states containing strange quarks -- hyperons offer excellent prospects discovering such baryons. Building up on novel calculations matrix elements relevant hyperon decays, in view various collider, flavor, astrophysical constraints, we determine expected rates factories like BESIII...

It has recently been shown [1] that light vector particles produced from inflationary fluctuations can give rise to the dark matter in Universe. A similar mechanism discussed [2] for a non-minimally coupled scalar enjoying Higgs portal interaction. We discuss detail how such generation of works minimal setup massive gravity. For suitable values non-minimal coupling any initial constant value field is suppressed during inflation. At same time, quantum acquired inflation peaked energy density...

B-mesogenesis is an elegant theory that could explain both the excess of matter over anti-matter in universe and abundance dark via B meson decays to a baryon anti-baryon. A thorough analysis necessary ingredients such models now shows they can be definitively tested at current factories LHC, offering potential gain insights into key aspects cosmology using flavor physics.

A weakly coupled and light dark photon coupling to lepton charges $L_\mu-L_\tau$ is an intriguing matter candidate whose coherent oscillations alter the dispersion relations of leptons. We study how this effect modifies dynamics neutrino flavor conversions, focusing on long baseline solar oscillations. analyze data from T2K, SNO, Super-Kamiokande experiments in order obtain world-leading limits gauge for masses below $\sim 10^{-11}\,\mathrm{eV}$. Degeneracies between shifts mass-squared...

A bstract We present the νϕ MTH, a Mirror Twin Higgs (MTH) model realizing asymmetric reheating, baryogenesis and twin-baryogenesis through out-of-equilibrium decay of right-handed neutrino without any hard $${\mathbb{Z}}_{2}$$ breaking. The MTH is simplest Neutral Naturalness solution to little hierarchy problem predicts existence twin dark sector related Standard Model (SM) by symmetry that only softly broken higher vacuum expectation value. reheating cools compared visible one, thus...

Motivated by their potential role as dark matter, we study the cosmological evolution of light scalar and vector fields non-minimally coupled to gravity. Our focus is on a situation where dominant contribution energy density arises from misalignment mechanism. In addition, also discuss possibility that matter generated in stochastic scenario or inflationary fluctuations. Even small deviations non-minimal couplings standard scenarios lead significant qualitative quantitative changes. This due...

A bstract Low-scale baryogenesis and dark matter generation can occur via the production of neutral B mesons at MeV temperatures in early Universe, which undergo CP-violating oscillations subsequently decay into a sector. In this work, we discuss consequences realizing mechanism supersymmetric model with an unbroken U(1) R symmetry is identified baryon number. sector through number conserving operator mediated by TeV scale squarks GeV Dirac bino. The particles be sterile neutrinos their...

We argue that demanding a consistent cosmological history, including the absence of domain walls and strongly interacting relics at Peccei-Quinn scale, singles out two concrete realizations hadronic QCD axions as viable dark matter models. These generally feature flavor-violating axion couplings to Standard Model quarks are unsuppressed low energies. As consequence, experiments looking for processes involving can be sensitive probes In particular, we show NA62 KOTO could detect...

Sterile neutrinos (νs) that mix with active (νa) are interesting dark matter candidates a rich cosmological and astrophysical phenomenology. In their simplest incarnation, production is severely constrained by combination of structure formation observations X-ray searches. We show if couple to an oscillating condensate very light Lμ-Lτ gauge field, resonant νa-νs oscillations can occur in the early universe, consistent νs constituting all matter, while respecting constraints on νs→νaγ...

The very low mass and small coupling of axion-like particles (ALPs) is usually taken as a guarantor their cosmological longevity, making them excellent dark matter candidates. That said, Bose enhancement could stimulate decays challenge this paradigm. Here, we analyze review the decay ALPs into photons, taking account, thereby going beyond usual naive perturbative estimate. At first glance, calculation seems to yield an exponentially growing resonance therefore extremely fast rate. However,...

Axion-like particles (ALPs) are interesting dark matter candidates both from the theoretical as well experimental perspective. Usually they motivated pseudo-Nambu-Goldstone bosons. In this case one of their most important features is that coupling to other suppressed by a large scale, vacuum expectation value field breaking symmetry gives rise them. This naturally endows them with very weak interactions but also restricts maximal and therefore regions where sufficient produced. paper we...

Evidence for a stochastic gravitational wave (GW) background, plausibly originating from the merger of supermassive black holes (SMBHs), is accumulating with observations pulsar timing arrays. An outstanding question how inspiraling SMBHs get past "final parsec" separation, where they have tendency to stall before GW emission alone can make binary coalesce. We argue that dynamical friction dark matter (DM) spike surrounding sufficient resolve this puzzle, if DM has self-interaction cross...

A bstract Dark matter from a hidden sector with SU( N ) gauge symmetry can have nonabelian kinetic mixing portal the standard model. The dark photon becomes massive in confining phase without need for spontaneous breaking. Depending on particle content of sector, there be two or more composite vectors that get through heavy mediator X . This provides model photons giving direct detection baryons. Avoiding exotic charged relics requires additional couplings allowing to decay quarks and...

A bstract Gauging a specific difference of lepton numbers such as L μ − τ is popular model-building option, which gives rise to economical explanations for the muon anomalous magnetic moment. However, this choice gauge group seems rather arbitrary, and additional physics required reproduce observed neutrino masses mixings. We address these shortcomings by embedding in vectorial SU(3) symmetry flavor. The vacuum expectation values (VEVs) scalar fields fundamental, six-dimensional adjoint...

Very light dark matter is usually taken to consist of uncharged bosons such as axion-like particles or photons. Here, we consider the prospect very light, possibly even sub-eV carrying a net charge that (approximately) conserved. By making use Affleck-Dine mechanism for its production, show sizable fraction energy density can be stored in asymmetric component. We furthermore argue there exist regions parameter space where contained symmetric particle-antiparticle pairs without some degree...

Sterile neutrinos can be produced in the early universe via interactions with their active counterparts. For small active-sterile mixing angles, thermal equilibrium standard model plasma is not reached and sterile are only flavor oscillations. We study detail this regime, taking into account matter potentials decoherence effects caused by elastic scatterings plasma. find that resonant oscillations occurring at temperatures T≲10 GeV lead to a significant enhancement of neutrino production...

The axion is much lighter than all other degrees of freedom introduced by the Peccei-Quinn mechanism to solve strong CP problem. It therefore natural use an effective field theory (EFT) describe its interactions. Loop processes calculated in EFT may, however, explicitly depend on ultraviolet cutoff. In general UV cutoff not uniquely defined, but dimensionful couplings suggest identify it with symmetry-breaking scale. An example are $K \rightarrow \pi + a$ decays that will soon be tested...

Dark photons coupling to $L_\mu-L_\tau$ lepton number difference are a highly studied light dark matter candidate, with potential be discovered through their impact on terrestrial neutrino oscillation experiments. We re-examine this in the of claimed tensions between NO$\nu$A and T2K long baseline experiments, also taking into account data from MINOS experiment. obtain leading limits gauge $g'$ versus photon mass $m_{A'}$, find no statistically significant alleviation tension inclusion new...

Most of the matter in universe is form dark matter. However, has never been observed to interact with normal laboratory experiments. ALPs -- ultralight axionlike particles are a class models that consistent astrophysical constraints, and produce measurable signatures oscillating violations discrete symmetries nuclei. We report first results from search for parity-odd time-reversal-odd nuclear moments $^{153}$Eu ions crystal, which leads an experimental constraint on ALP-gluon coupling...