This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision | ||
2017:groups:tools:susylha [2017/06/22 17:37] fabio.maltoni [The details] |
2017:groups:tools:susylha [2017/06/22 22:22] (current) fabio.maltoni |
||
---|---|---|---|
Line 1: | Line 1: | ||
====== Extension to the SLHA for cross sections ====== | ====== Extension to the SLHA for cross sections ====== | ||
- | Interested people: Olivier Mattelaer, Sezen, Benjamin, Stefan ... 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. | Work started in LH 2013. Already quite complete. Needs to be polished and written up. Need to get agreement for the SUSY code developers. | ||
Line 21: | Line 21: | ||
This general information line is then followed by the cross section themselves, given as a series of line under the form | This general information line is then followed by the cross section themselves, given as a series of line under the form | ||
<code> | <code> | ||
- | SCALE_SCHEME QCD_ORDER EW_ORDER KAPPA_F KAPPA_R PDF_ID1 PDF_ID2 VALUE VALUEPDFUP VALUEPDFDOWN | + | SCALE_SCHEME QCD_ORDER EW_ORDER KAPPA_F KAPPA_R PDF_ID1 PDF_ID2 VALUE VALUEUP VALUEDOWN DUMMY |
</code> | </code> | ||
+ | |||
+ | |||
where | where | ||
* **SCALE_SCHEME**: an integer number, related to the way the central scales are chosen. So far, the choices are | * **SCALE_SCHEME**: an integer number, related to the way the central scales are chosen. So far, the choices are | ||
Line 30: | Line 32: | ||
* 3: the scale is set to the transverse 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 | * 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. This is codified as | + | * **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: Born cross section | + | * 0=LO, |
- | * 1: NLO cross section | + | * 1=NLO, |
- | * 2: NLO+NLL cross section | + | * 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 | * **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_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. | ||
Line 39: | Line 46: | ||
* **PDF_ID**: the lhapdf code of the employed parton densities | * **PDF_ID**: the lhapdf code of the employed parton densities | ||
* **VALUE**: a floating point number, representing the value of the cross section in pb. | * **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 | * 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 | * VERSION: as a COMMENT string, the version number of the proram employed | ||
Line 44: | Line 52: | ||
* FIX the meaning of DEFAULT values... | * FIX the meaning of DEFAULT values... | ||
- | Olivier Questions: | ||
- | - Do we really want to have 1 line for each PDF replica? Would not be better to quote the theoretical uncertainty in % ? | ||
- | - What about non LHC collision (fix target/ DIS/...)? This requires 2 PDF id. | ||
- | - other scheme are often used like HT/2 and (CKKW ones) are not even analytic. | ||
- | - What about NNLO or NNLL? | ||
- | - using some xml tag in a non xml like file is weird (or I do not understand where you plan to write such information). | ||
- | - Missing the information of the statistical uncertainty | ||
- | |||
Stefan comments: | Stefan comments: | ||
- | - PREFERRED OPTION: In order to deal with resummation I suggest to add a second digit to QCD_ORDER, i.e. 0=LO, 1=NLO, 2=NNLO, etc. 11=NLO+NLL, 21=NNLO+NLL, 22=NNLO+NNLL, etc.. Only LO+LL=00 is then not well defined. And this approach is not specific to what is actually resummed (p_T, threshold,...). TYPE of resummation as a COMMENT. | ||
- | - | ||
- 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. | - 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. | ||
- | - | ||
- | - Some codes also give a scale uncertainty in the same run. Can this be added? |