CMSSM < Sandbox

-- Main.EfstathiosMegas - 25 Jan 2014
---+ Higgs-aware scan of m0-m1/2 plain of cMSSM at 8TeV and tan(beta)=30

<br />%TOC%

---++ the parameters of the cMSSM

For this scan, <span style="background-color: transparent;">the following values for the parameters were selected :</span>

* tan(beta) = 30

* sign(&mu;) = +1

* the common trilinear coupling was set to A_0 = -2 max(m0, m1/2), as suggested in http://arxiv.org/pdf/1204.5977v2.pdf,<span style="background-color: transparent;"> in order to obtain a maximal stop mixing that would result in a more appropriate mass for the higgs in the small-m0 region</span>

<span style="background-color: transparent;">* for the m0 and m1/2 parameters a grid of 664 points was chosen to be scanned. Out of those points, 58 were excluded because they corresponded to stau (with pdg code 1000015) being the LSP (as shown in the figure below)</span>

<span style="background-color: transparent;"><img width="561" alt="stau_LSP_region.png" src="https://twiki.cern.ch/twiki/pub/Sandbox/CMSSM/stau_LSP_region.png" title="stau_LSP_region.png" height="420" /><br /></span>

---++ the standard model inputs

The following selection of values was made :

top mass = 172.5 <noautolink> G<span style="background-color: transparent;">eV </noautolink></span>

tau mass = 1.777 <span style="background-color: transparent;"><noautolink></span>GeV<span style="background-color: transparent; color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre;">&lt;/noautolink&gt;</span><span style="background-color: transparent;"> </span>

<span style="color: #7a4707; font-size: 10px; line-height: 20.474998474121094px;"> </span><span style="background-color: transparent;">Z mass = 91.1876 </span><span style="color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre;">&lt;noautolink&gt;</span>GeV<span style="color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre; background-color: transparent;">&lt;/noautolink&gt;</span>

mb(mb)^MSbar = 4.2

alpha_em^-1(M_Z)^MSbar = 127.934

G_F [GeV^-2] = 1.16637 E-05<span style="background-color: transparent;"> </span>

alpha_S(M_Z)^MSbar = 0.1184

---++ the scanned grid

<span style="background-color: transparent;">The scan includes 606 points placed on a multi-rectangular grid which is divided into 9 regions (as shown in the figures below)</span>

<span style="background-color: transparent;"><img width="561" alt="the_9_regions.png" src="https://twiki.cern.ch/twiki/pub/Sandbox/CMSSM/the_9_regions.png" title="the_9_regions.png" height="420" /><br /></span>

<img width="561" alt="the_regions_without_stau_LSP.png" src="https://twiki.cern.ch/twiki/pub/Sandbox/CMSSM/the_regions_without_stau_LSP.png" title="the_regions_without_stau_LSP.png" height="420" />

<span style="background-color: transparent;">As it is apparent, each of the 9 regions has one out of 4 possible steps for m0. This diversification for the step of m0 was chosen in order to optimally concentrate in the interesting region near the origin of the plain, since for large m0 the rejection lines are expected to be parallel to the m0 axis, and thus a bigger step can be chosen.</span>

---++ the spectrum, decay rates, cross sections and the events

For each selected point, the mass spectrum was calculated using SOFTSUSY, and the decay rates using SUSYHIT. That information was stored in slha files based on which 150,000 events per point were produced with Pythia at 8 <span style="color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre;">&lt;noautolink&gt;</span>TeV<span style="color: #7a4707; font-family: 'Courier New', courier, monaco, monospace; white-space: pre;">&lt;/noautolink&gt;</span><span style="background-color: transparent;">.</span>

The cross sections were calculated at NLO using prospino.

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
png	stau_LSP_region.png	r1	manage	6.0 K	2014-01-25 - 19:21	EfstathiosMegas
png	the_9_regions.png	r1	manage	5.6 K	2014-01-25 - 19:21	EfstathiosMegas
png	the_regions_without_stau_LSP.png	r1	manage	5.5 K	2014-01-26 - 12:07	EfstathiosMegas

Topic revision: r6 - 2014-01-30 - EfstathiosMegas

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