LUX likelihood and limits on spin-independent and spin-dependent WIMP couplings with LUXCalc

Abstract

We present LUXCalc, a new utility for calculating likelihoods and deriving WIMP-nucleon coupling limits from the recent results of the LUX direct search dark matter experiment. After a brief review of WIMP-nucleon scattering, we derive LUX limits on the spin-dependent WIMP-nucleon couplings over a broad range of WIMP masses, under standard assumptions on the relevant astrophysical parameters. We find that, under these and other common assumptions, LUX excludes the entire spin-dependent parameter space consistent with a dark matter interpretation of DAMA's anomalous signal, the first time a single experiment has been able to do so. We also revisit the case of spinindependent couplings, and demonstrate good agreement between our results and the published LUX results. Finally, we derive constraints on the parameters of an effective dark matter theory in which a spin-1 mediator interacts with a fermionic WIMP and Standard Model fermions via axial-vector couplings. A detailed appendix describes the use of LUXCalc with standard codes to place constraints on generic dark matter theories. arXiv:1502.02667v3 [hep-ph] 12 May 2015 2 Notably, G N SI are the G F -like effective four-fermion coupling constants in the case of scalar interactions [16] and are the normalization used in DarkSUSY [17]. MicrOMEGAs uses λ N = 1 2 G N SI [18].

Multicomponent Dark Matter from gauge symmetry

“…(3.24) 10 over a suitable range of recoil energies and multiplied the result with the number of nuclei and the exposure time in a given experiment. Given the design similarity between the LUX and XENON1T experiments, we have assumed the upper limit of 3 events for both (with two years of exposure time) [45]. This number takes into account the detector efficiency which is set to 1 in Micromegas.…”

“…Therefore, both the pseudoscalar and the vector DM 10 The correct number of recoil events is actually given by the convolution of eq. (3.24) with a function accounting for the detector efficiency and finite energy resolution [45,46]. Neglecting this function implies an overestimate of the number of recoil events for a given scattering cross-section.…”

Dark matter interpretations of ATLAS searches for the electroweak production of supersymmetric particles in s = 8 $$ \sqrt{s}=8 $$ TeV proton-proton collisions

“…For the spin-independent cross section, the LUX data from 85.3 live-days with a fiducial volume of 118 kg [71] is used, as this result became available in time to be included in the analysis. The LUX limit was included using the likelihood computed by the LUXCalc package [78]. The likelihood is constructed from a Poisson distribution in which the numbers of observed and background events are 1 and 0.64, respectively.…”

Effective field theory treatment of the neutrino background in direct dark matter detection experiments

“…After the 99.6% electronic recoil discrimination efficiency, 1.9 events were expected in the nuclear recoil region, and 2 were actually observed. The energy dependent detector efficiency was taken from LUXcalc [41], which takes into account detector resolution and threshold effects. While this efficiency curve is based on the 2013 LUX analysis, we have reduced the threshold to 1.1keV in line with the more recent analysis.…”