English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Recently, the ATLAS and CMS collaborations report excesses around $750$ GeVin the diphoton channels. This might be the evidence which reveals new physicsbeyond the Standard Model. In this paper, we consider models with a $750$ GeVscalar and vector-like particles, which couple each other through Yukawacouplings. The diphoton decay of the scalar is enhanced by the loop diagramsinvolving the extra colored particles. We investigate not only the setuprequired by the excesses, but also the LHC constraints, especially concernedwith the vector-like particles. We consider the scenario that the extra coloredparticles decay to quarks and a dark matter (DM) via Yukawa couplings. Then,the signals from the vector-like particles are dijet, $b\overline{b}$ and/or$t\overline{t}$ with large missing energy. We discuss two possibilities for thesetups: One is a model with vector-like fermions and a scalar DM, and the otheris a model with vector-like scalars and a fermionic DM. We suggest theparameter region favored by the excess in the each case, and study theconstraints based on the latest LHC results at $\sqrt{s}=8$ TeV and $13$ TeV.We conclude that the favored region is almost excluded by the LHC bounds,especially when the $750$ GeV scalar dominantly decays to DMs. The massdifferences between the vector-like particles and the DM should be less than${\cal O}(100)$ GeV (${\cal O}(10)$ GeV) to realize the large diphoton signaland the large decay width, if the extra colored particle only decays to a top(bottom) quark and a DM. Otherwise, these scenarios are already excluded by thelatest LHC results.

Diphoton excess at 750 GeV and LHC constraints in models with vector-like particles