Search for $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ charged dark matter with neutrino telescope

Abstract

A bstract We study a simple Dirac fermion dark matter model in $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>U</mml:mi><mml:msub><mml:mfenced><mml:mn>1</mml:mn></mml:mfenced><mml:mrow><mml:msub><mml:mi>L</mml:mi><mml:mi>μ</mml:mi></mml:msub><mml:mo>−</mml:mo><mml:msub><mml:mi>L</mml:mi><mml:mi>τ</mml:mi></mml:msub></mml:mrow></mml:msub></mml:math> theory. The new light gauge boson X plays important roles in both dark matter physics and the explanation for the muon g − 2 anomaly. The observed dark matter relic density is realized by a large $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>U</mml:mi><mml:msub><mml:mfenced><mml:mn>1</mml:mn></mml:mfenced><mml:mrow><mml:msub><mml:mi>L</mml:mi><mml:mi>μ</mml:mi></mml:msub><mml:mo>−</mml:mo><mml:msub><mml:mi>L</mml:mi><mml:mi>τ</mml:mi></mml:msub></mml:mrow></mml:msub></mml:math> charge without introducing a resonance effect of the X boson. As a by-product of the model, characteristic neutrino signatures from sub-GeV dark matter ψ are predicted depending on the mass spectrum. We formulate the analysis of $$ \psi \overline{\psi}\to \nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ψ</mml:mi><mml:mover><mml:mi>ψ</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mo>→</mml:mo><mml:mi>ν</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math> , and of $$ \psi \overline{\psi}\to XX $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ψ</mml:mi><mml:mover><mml:mi>ψ</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mo>→</mml:mo><mml:mi>XX</mml:mi></mml:math> followed by $$ X\to \nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>X</mml:mi><mml:mo>→</mml:mo><mml:mi>ν</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math> in a model independent way. The energy spectrum of neutrinos in the former process is monochromatic while in the latter process is bowl-shape. We also evaluate sensitivity at Super-Kamiokande and future Hyper-Kamiokande detectors. The analysis is finally applied to the $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>U</mml:mi><mml:msub><mml:mfenced><mml:mn>1</mml:mn></mml:mfenced><mml:mrow><mml:msub><mml:mi>L</mml:mi><mml:mi>μ</mml:mi></mml:msub><mml:mo>−</mml:mo><mml:msub><mml:mi>L</mml:mi><mml:mi>τ</mml:mi></mml:msub></mml:mrow></mml:msub></mml:math> dark matter model.

Topics & Concepts