Likelihood analysis of the pMSSM11 in light of LHC 13-TeV data

Abstract

We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from

∼ 36

/fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the

( g - 2 )

μ

constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses

M

1 , 2 , 3

, a common mass for the first-and second-generation squarks

m

q ~

and a distinct third-generation squark mass

m

q ~

3

, a common mass for the first-and second-generation sleptons

m

ℓ ~

and a distinct third-generation slepton mass

m

τ ~

, a common trilinear mixing parameter A, the Higgs mixing parameter μ , the pseudoscalar Higgs mass

M A

and

tan β

. In the fit including

( g - 2 )

μ

, a Bino-like

χ ~

1 0

is preferred, whereas a Higgsino-like

χ ~

1 0

is mildly favoured when the

( g - 2 )

μ

constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino,

χ ~

1 0

, into the range indicated by cosmological data. In the fit including

( g - 2 )

μ

, coannihilations with

χ ~

2 0

and the Wino-like

χ ~

1 ±

or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the

χ ~

2 0

and the Higgsino-like

χ ~

1 ±

or with first- and second-generation squarks may be important when the

( g - 2 )

μ

constraint is dropped. In the two cases, we present

χ 2

functions in two-dimensional mass planes as well as their one-dimensional profile projections and best-fit spectra. Prospects remain for discovering strongly-interacting sparticles at the LHC, in both the scenarios with and without the

( g - 2 )

μ

constraint, as well as for discovering electroweakly-interacting sparticles at a future linear

e +

e -

collider such as the ILC or CLIC.