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--- 2017:groups:np:qfvlhc [2017/06/19 17:38]
bjoern.herrmann
+++ 2017:groups:np:qfvlhc [2017/09/11 15:29] (current)
priscilla.pani [References]
@@ Line 1: / Line 1: @@
 ====== Squark decays beyond MFV at LHC ======
-People: Priscilla Pani, Giacomo Polesello, Amit Chakraborty, Björn Herrmann, Benjamin Fuks, Mihoko Nojiri, Abishek Iyer
+People: Priscilla Pani, Giacomo Polesello, Amit Chakraborty, Björn Herrmann, Benjamin Fuks, Mihoko Nojiri, Abishek Iyer, Ramona Gröber
+Email: <priscilla.pani@cern.ch>, <giacomo.polesello@cern.ch>, <herrmann@lapth.cnrs.fr>, <amit@post.kek.jp>, <fuks@lpthe.jussieu.fr>, <nojiri@post.kek.jp>, <abhishek@theory.tifr.res.in>, <ramona.groeber@durham.ac.uk>
 ==== Idea ====
   * Investigate QFV signature:  ''pp -> t j ETmiss''
   * Start by implementing a simplified model, then try to move on to more realistic case.
 ==== Setup ====
-We start by investigating a simplified model setup as follows.
+We start by investigating a simplified model setup as follows. We complement the SM by a right-handed scharm (scR) and stop (stR).
-The two-squark system is parametrized with the parameters:
+In the gauge eigenbasis, the two-squark system is parametrized with the three parameters:
-  * mSt (stop mass parameter),
+  * Mst (stop mass parameter),
-  * mSc (scharm mass parameter),
+  * Msc (scharm mass parameter),
-  * mStc (mixing parameter).
+  * Mstc (mixing parameter).
-After diagonalisation, the physical parameters are:
+After diagonalisation, in the mass eigenbasis, the three physical parameters are:
-  * mSq1 (lighter squark),
+  * Msq1 (lighter squark),
-  * mSq2 (heavier squark),
+  * Msq2 (heavier squark),
-  * thSq (mixing angle),
+  * theta (mixing angle),
-such that Sq1 = cos(thSq)*St + sin(thSq)*Sc.
+such that sq1 = ct*scR + st*St (and the corresponding relation for the second squark state sq2).
-Moreover, we consider:
+In addition, we add to the model a gluino (go), with the appropriate SUSY mixings (so that it will contribute to the various production process) and a bino (chi) that will allow both squarks to decay. The corresponding mass parameters are
-  * mN1 (neutralino mass),
+  * Mchi (neutralino mass),
-  * mGl (gluino mass).
+  * Mgo (gluino mass).
-Put model files here...
+The FeynRules model file is available {{stop_scharm.fr.tgz|here}}, and the corresponding UFO {{st-sch.ufo.tgz|there}}. Do not forget, in madgraph, to load the model as
+<code> import model stop-scharm_UFO -modelname </code>
+and that the neutralino is called chi (and not n1).
 ==== Working plan ====
@@ Line 41: / Line 42: @@
 . From the above, deduce cross-sections ''pp -> t t ETmiss'', ''pp -> c c ETmiss'', ''pp -> t c ETmiss'': functions of mSq1, mSq2, thSq, mN1. Make sure to seperate contributions from different subchannels, since this information is necessary to determine the experimental acceptance!
-. Compute the above signal cross-sections in the full model (i.e. with 4x4 mixing) and use the obtained acceptances to deduce the limits.
+. Compute the above signal cross-sections in the full model (i.e. with 4x4 mixing) and use the obtained acceptances to deduce the limits. For this, we will use analytical formulas tu compute the BR. NLO+NLL cross sections for the signal.
+. At the end, try a different bino mass (50 GeV as default, and let's increase it). Try also to include BR of the squarks into something else (that is not populating the signal regions). Finally, maybe get the gluino mass dependence.
+==== Plots and documents ====
+{{qfvlhc_sigQQ.pdf | diagonal production, th=0}}
+{{qfvlhc_sig-mix1.pdf | mixed production, th=pi/2}}
+{{qfvlhc_sig-mix2.pdf | mixed production, th=pi/4}}
+{{qfv_leshouches_summary.pdf | Les Houches Summary Slides}}
+{{qfv_note.pdf | Note}}
+== Rescaling of exclusion by BR ==
+This set of macro was created to automatically rescale the scharm and stop analyses in the reference (8TeV 20ifb results) for any assumptions of mixing and U-masses. Download the full directory: {{ :2017:groups:np:nmfvstop.tgz |}}
+Execution Command (to be run in the working directory - run python rescaleExclusion.py --help for parameters explanation )
+python rescaleExclusion.py --u1max 1000 --u1min 400 --step 100 --lumi 20 --alphalist 4,8 --Mchi 50
+(NOTE before each parameter you need two dashes, I cannot make it appear in the twiki FIXME)
+----
 ==== References ====
+  * "Squark and gaugino hadroproduction and decays in non-minimal flavour violating supersymmetry" [[https://arxiv.org/pdf/0704.1826.pdf| (arXiv)]]
   * "Impact of squark generation mixing on the search for squarks decaying into fermions at LHC", [[https://arxiv.org/pdf/1007.5483.pdf| (arXiv)]]
   * "General squark flavour mixing: constraints, phenomenology and benchmarks" [[https://arxiv.org/pdf/1509.05414.pdf| (arXiv)]]
   * "Gluino Meets Flavored Naturalness" [[https://arxiv.org/pdf/1512.03813.pdf| (arXiv)]]
+  * "Light stop decays" [[https://arxiv.org/pdf/1408.4662.pdf| (arXiv)]]
+  * "Light stop decays into WbN1 near the kinematic threshold" [[https://arxiv.org/pdf/1502.05935.pdf| (arXiv)]]
+  * "Search for top squark pair production in final states with one isolated lepton, jets, and missing transverse momentum in s√= 8 TeV pp collisions with the ATLAS detector" [[https://arxiv.org/abs/1407.0583|(arXiv)]]
+  * "Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at s√s = 8 TeV with the ATLAS detector" [[https://arxiv.org/abs/1410.5404|(arXiv)]]

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