ALPino cosmology and its
detection prospect

Osamu Seto (Hokkaido Univ.)
With: Ki-Young Choi, Takeo Inami, Kenji Kadota , Inwoo Park
Ref : 1902.10475

§Introduction• Axion (a) is interesting.
– A solution to the Strong CP problem– Astrophysical and cosmological constraints– Good DM candidate• General axion: Axion-like Particles (ALPs)– Universal : e.g., String Compactification, Axiverse, …
– Mass and decay constant as free parameters• Today, we consider ALP mass larger than QCD axion’s.

§Introduction[Alekhin et al (2016)]• Axion (a) is interesting.
– A solution to the Strong CP problem– Astrophysical and cosmological constraints– Good DM candidate• General axion: Axion-like Particles (ALPs)– Universal : e.g., String Compactification, Axiverse, …
– Mass and decay constant as free parameters• Today, we consider ALP mass larger than
QCD axion’s.
Heavy ALPs is an interesting to explore§Introduction• Axion (a) is interesting.
– A solution to the Strong CP problem– Astrophysical and cosmological constraints– Good DM candidate• General axion: Axion-like Particles (ALPs)– Universal : e.g., String Compactification, Axiverse, …
– Mass and decay constant as free parameters• Today, we consider ALP mass larger than QCD axion’s.

• Supersymmetry– Superparticle

§ Supersymmetric model with ALPs

Model• Superpartner of ALP: ALPino ã– Analogus to Axino• Fa suppressed interaction• Could be the lightest supersymmetric particle, LSP,
which is stable for a R-parity conserving model.
• Dark matter candidate– axion decay constant as a free parameter• Free fa suppression• Interaction (ALPino-photino-photon)

Model• Superpartner of ALP: ALPino ã• Interaction (ALPino-photino-photon)• Mass spectrum– ALPino LSP (good DM candidate too)
– Bino-like neutralino NLSP

• Free parameter– ALPino mass [Chun, Kim, and Nilles (1992), Chun and Lukas(1992)], ALPs decay constant, Neutralino mass

§ ALPino cosmology : ALPino asdark matter

Review of axino dark matter• ALPino : a variant of axino• Axino dark matter [Covi et al (1999)]– Interaction– Production• Scattering and decay in thermal plasma• Nonthermal production: decay of NLSP

Review of axino dark matter• Abundance• Proportional to TR/fa2[Choi et al (2012)]

Review of axino dark matter• Abundance• Proportional to TR/fa2

ALPino: Smaller fa[Choi et al (2012)]

ALPino abundance• Freeze out temperature• Thermal relic?
– For Tf > mã , hot relic– For Tf < mã , fa > 104 GeV leads to overabundance• A way out– Non-thermal production with a low reheating
temperature (TR  m )

ALPino abundance• A way out– Non-thermal production with a low reheating
temperature (TR  m )• → Integrated to TR• →• Problem of baryogenesis… (as in Axino DM…)§ ALPino detection :as a long-lived particle

Model• Superpartner of ALP: ALPino ã• Interaction (ALPino-photino-photon)• Process• Detection– CHARM, NOMAD, SHiP– c ~100 m§§ Production• in SHiP– SPS: energy = 400 GeV ( s ~27.4 GeV)
– Nproton ~ 2 1020 for 5 years [Alekhin et al (2016)]• The number of produced mesons– Multiplicity[Becattini and Heinz (1997)]– For J/ and B••

M : meson production per nucleon J/ ~ 200 nb, B ~ 3.6 nb§§ ALPino in the fixed target• The decay rate of the neutralino• Lifetime• Reference scale: for c ~100 m

§§ ALPino in the fixed target• The number of neutralino decay events– l : distance from the target = 70 m
– l : decay volume length = 55 m
DetectorTargetlp

l§§ Constraints and Prospect 1
mã = 10 MeVtan = 10
 = 100 TeV
msquark = 10 TeVCAHRM, NOMAD
with Nee~2
N>3 for SHiP
Mono-X by dipole
for Tevatron, LHC, LEP§ Summary• ALPino: super-partner of ALPs
• c of the neutralino decay is (100) m• Range of search– Light neutralino < GeV– Decay constant f ~ 105 GeV