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--- 2017:groups:tools:susylha [2017/06/19 17:00]
olivier.mattelaer
+++ 2017:groups:tools:susylha [2017/06/22 22:22] (current)
fabio.maltoni
@@ Line 1: / Line 1: @@
-SUSY
+====== Extension to the SLHA for cross sections ======
-Interested people: Olivier Mattelaer, .... ADD YOUR NAME
+Interested people: Olivier Mattelaer, Sezen Sekmen, Benjamin Fuks, Stefan Liebler, Michael Spira, Fabio Maltoni... ADD YOUR NAME
+Work started in LH 2013.  Already quite complete.  Needs to be polished and written up. Need to get agreement for the SUSY code developers.
+==== The details ====
+The plans is to add new blocks to a supersymmetric spectrum with information on production cross section of particles included in the spectrum of interest. We propose to add one new block for each process under consideration.
+The block starts with
+<code>
+XSECTION SQRTS PDG_CODE1 PDG_CODE2 NF PDG_CODE3 ....
+</code>
+where
+  * **SQRTS**: a floating number representing the center-of-mass energy, to be given in GeV.
+  * **PDG_CODE1** and **PDG_CODE2**: two integer numbers, representing the pdg codes of the initial state particles
+  * **NF**: an integer number, representing the number of final state particles
+  * **PDG_CODE3**, **PDG_CODE4**, ...: NF integer numbers, representing the pdg codes of the final state particles
+This general information line is then followed by the cross section themselves, given as a series of line under the form
+<code>
+  SCALE_SCHEME QCD_ORDER EW_ORDER KAPPA_F KAPPA_R PDF_ID1 PDF_ID2 VALUE VALUEUP VALUEDOWN DUMMY
+</code>
+where
+  * **SCALE_SCHEME**: an integer number, related to the way the central scales are chosen. So far, the choices are
+    * 0: the central scale is the average mass of the produced particles
+    * 1: fixed scales
+    * 2: the scale is set to the invariant mass of the final state particles at the LO
+    * 3: the scale is set to the transverse mass of the final state particles at the LO
+    * 4: some other definition to be described as a comment
+  * **QCD_ORDER**: an integer number, which contains information on the order in alpha_s included in the computation. In order to deal with resummation I suggest to add a second digit to QCD_ORDER, i.e.
+    * 0=LO,
+    * 1=NLO,
+    * 2=NNLO,
+    * 3=N3LO,
+    * 11=NLO+NLL,
+    * 21=NNLO+NLL,
+    * 22=NNLO+NNLL,
+    *  TYPE of resummation as a COMMENT.
+  * **EW_ORDER**: same as above but with respect to electroweak corrections
+  * ** KAPPA_F**: a floating point number, related to the variation of the factorization scale with respect to the central scale. For SCALE_SCHEME set to 1, the scale itself has to be provided.
+  * ** KAPPA_R**: same as above, for the renormalization scale
+  * **PDF_ID**: the lhapdf code of the employed parton densities
+  * **VALUE**: a floating point number, representing the value of the cross section in pb.
+  * **DUMMY**: integer number to tag possible different options to be described in the comments
+  * CODE: as a COMMENT string representing the name of the program which has computed the cross section
+  * VERSION: as a COMMENT string, the version number of the proram employed
+  * REFERENCE: Citation
+  * FIX the meaning of DEFAULT values...
+Stefan comments:
+  - OPTIONAL: For EW corrections it would be helpful to somehow encode if full factorization is assumed or not. => Implement as a comment what scheme is used to combine QCD and EW corrections.

Les Houches

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