Added DMsimp_tchannel model + info
Please merge so that Deepak can use the model. I've included the model directory as well as some info in the text file, as follows:
Requestor: Deepak Kar Content: T-channel simplified dark matter model for semi-visible jets Webpage: https://github.com/smsharma/SemivisibleJets JIRA: https://its.cern.ch/jira/browse/AGENE-1753
Thank you!