Program Manual and input-file guide for HiggsPt version 1.2

This manual describes how to use the program HiggsPt, which computes the Higgs boson Transverse Momentum distribution at NLO in the limit of large top quark mass. The manual gives line-by-line instructions for the input file "HiggsPt.indat".

General Formatting Notes:

It should be fairly easy to use the input file, "HiggsPt.indat", just by modifying the example that came with the source distribution. However, there are a few general formatting requirements to be aware of.
The input file must have exactly 12 lines.
In the following explanations of the inputs, a list {a, b, c} indicates a choice of string inputs on a line, while an ordered list [x y z] indicates multiple numerical parameters input on a single line. Possible inputs are colored red.
If the input to a line is a string, then it MUST have trailing white spaces after the string (NOT TABS!). It is easiest to do this by keeping the explanatory comment after the input string (i.e, white spaces followed by #x Comment) from the example file.
Any input which is a string must be spelled exactly as given below, including capitalization and without quotation marks, or else the program will complain.
The program ignores anything in a line that comes after the expected input.

Line-by-line explanation of input file:

#1 Name of the output file.
Any file name will do, such as output/HiggsPt.out (without quotes). There is an empty directory "output/" in the same directory as the executable, which may be used for output files. Or you may organize as you desire.
#2 Type of collider.
Choose from {pp, ppbar}.
#3 Collider COM energy
Input in GeV, such as 14000.0
#4 PDF file name.
The file name (such as cteq6m.LHpdf) for the particular PDF distribution to be used. The LHAPDF script "lhapdf-config" determines the correct path to the file, so make sure that the script is in the system $PATH.
#5 PDF member set.
This is an integer, which specifies the specific member set for the given PDF distribution. The default of 0 gives the "best fit" for any distribution. For more info, read the LHAPDF manual at
#6 Choice of Ren/Fact Scale Variable.
Choose from {MH, MT}.
MH :       muScale = M_H   (Higgs Mass)
MT : muScale = M_T = sqrt(M_H^2+p_T^2)  (Higgs Transverse Mass)
#7 Input scale choices.
The input format is [chiR chiF]. For example, 1.0 1.0.
The scale factors are defined by:
#8 Order of Calculation.
Choose from {LO_MT, LO, NLO}.
These give the order of the cross section to be calculated. (To be precise, NLO computes the sum of order alpha_s^3 and order alpha_s^4 corrections here.) If LO_MT is chosen, then the full top quark mass dependence is included (only available at LO); otherwise, the cross section is calculated in the limit of infinite top quark mass.
#9 Limit of Calculation.
Choose from {EXACT, SMALLPT}.
If SMALLPT is chosen, then calculate in the small-pt limit.

Lines #10, #11, and #12 are used for choosing which distribution is to be calculated (i.e, which parameters are to be varied while calculating the cross section). The inputs for the successive lines will depend on the choice of distribution in line #10.
#10 Choice of distribution.
Choose from {PT, Y}.
Renormalization :      mu_R=chiR*muScale.
Factorization : mu_F=chiF*muScale.
PT :       Calculate the cross section as a function of Higgs Transverse momentum for fixed Higgs mass and Higgs rapidity.
Y : Calculate the cross section as a function of Higgs rapidity for fixed Higgs mass and Higgs transverse momentum.
#11, #12 Distribution parameters.
The input here depends on the specific distribution choice in line #10.
PT :      
Line #11
Input the Higgs boson mass (in GeV) and rapidity: [M_Higgs, y_Higgs]. For example, 120.0 0.0.
Line #12
Input the values for Higgs transverse momentum (in GeV): [ptmin ptstep ptnumber] = [Lowest value of pt, step size in pt, number of pt values - 1].
For example, an input of 30.0  20.0  10 would produce a distribution in Higgs pt, running from 30.0 GeV to 230.0 GeV, with a step size of 20.0 GeV.
Y :
Line #11
Input the Higgs boson mass and transverse momentum (in GeV): [M_Higgs, pt_Higgs]. For example, 120.0 50.0.
Line #12
Input the values for Higgs rapidity: [ymin ystep ynumber] = [Lowest value of y, step size in y, number of y values - 1].
For example, an input of 0.0  0.5  8 would produce a distribution in Higgs rapidity from 0.0 to 4.0 with a step size of 0.5.