Problem in h > b b~ g

Dear ycwu,

Only fixed-order NLO (i.e., without (matching to) the parton shower) is possible for decay processes. Furthermore, a gluon is not a well-defined object at NLO, hence, you'll have to do

generate h > b b~ j [QCD]

where 'j' is defined as all the massless quarks and the gluon.

Best regards,
Rikkert

Note that I just notice a bug with the question in our development version, where it was setting as default fix order on False:

The following patch fix that issue:

=== modified file 'madgraph/interface/amcatnlo_run_interface.py'
--- madgraph/interface/amcatnlo_run_interface.py 2018-08-27 14:51:23 +0000
+++ madgraph/interface/amcatnlo_run_interface.py 2018-11-02 20:17:54 +0000
@@ -1053,7 +1053,10 @@

         if self.last_mode in ['LO', 'NLO']:
             self.switch['fixed_order'] = 'ON'
- self.switch['fixed_order'] = 'OFF'
+ if self.proc_characteristics['ninitial'] == 1:
+ self.switch['fixed_order'] = 'ON'
+ else:
+ self.switch['fixed_order'] = 'OFF'

     def color_for_fixed_order(self, switch_value):

@@ -1158,6 +1161,10 @@
         if self.last_mode in ['LO', 'NLO', 'noshower', 'noshowerLO']:
             self.switch['shower'] = 'OFF'
             return
+
+ if self.proc_characteristics['ninitial'] == 1:
+ self.switch['shower'] = 'OFF'
+ return

         if os.path.exists(pjoin(self.me_dir, 'Cards', 'shower_card.dat')):
             self.switch['shower'] = self.run_card['parton_shower']

Cheers,

Olivier

Thanks Olivier.

Cheers,
Rik

Hi Rik:
    After regenerating the process with:
generate h > b b~ j [QCD]

the MG5 still produce the same error .
Am I doing something wrong?

Best
ycwu

Dear ycwu,

Are you including matching to the parton shower or are you running at fixed order? As pointed out in my first message, only the latter is possible with decay processes.

Best,
Rikkert

Dear Rikkert:
    I was running at Fixed Order. But it still throw error:

xxxxx/xxxxx/ajob1 1 all 1 2 launch ends with non zero status: 139. Stop all computation

Thanks!

Best
ycwu

Dear ycwu,

I just tried myself and the code runs without problems for this process. I'm using the latest public version.
Do the log files in the <YourProcess>/SubProcesses/P*/all_G*/ directories give you any hint on the problem?

Best,
Rikkert

Dear Rikkert:
    I saw in SubProcesses/P0_h_bbxg/all_G1_*/log.txt following errors (lots of such errors, so I just pick two lines):

ERROR in OneLOop dilog2_r: j1, j2, r1-r2 -2 0, .00000000000E+00, returning 0
ERROR in OneLOop log1_r: rr,jj = .1000000000000000E+01 -2 , putting jj to 0

And in all_G1_1/log.txt, there is Segmentation fault:

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 0x7F1E6E706697
#1 0x7F1E6E706CDE
#2 0x7F1E60E012EF
#3 0x7F1E60F21774
#4 0x7F1E6E7DAAC3
#5 0x7F1E6E7D1DF2
#6 0x455ABA in void fastjet::ClusterSequenceArea::initialize_and_run_cswa<fastjet::PseudoJet>(std::vector<fastjet::PseudoJet, std::allocator<fastjet::PseudoJet> > cons t&, fastjet::JetDefinition const&)
#7 0x4819B7 in std::vector<int, std::allocator<int> >::_M_insert_aux(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)
#8 0x47B191 in std::vector<int, std::allocator<int> >::_M_insert_aux(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)
#9 0x47CDC6 in std::vector<int, std::allocator<int> >::_M_insert_aux(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)
#10 0x7F1E60DED444
#11 0x409ED7
#12 0xFFFFFFFFFFFFFFFF

I have no idea about this. I'm using the MG5-2.6.3.2

Thanks!
ycwu

Dear ycwu,

Hmm... I've not seen this error before and I'm not sure what's going on. It looks a bit like a compiler issue. Maybe some incompatibility in the compilation of fastjet (which is C++) and MG5_aMC (which is in Fortran). I'm not sure though. Olivier do you have a clue?

Best,
Rikkert

Hi,

Did you link MG5aMC to your own version of fastjet?
Or did you use the built-in one shipped with the code (fjcore)

Cheers,

Olivier

Hi Olivier:
    I linked MG5aMC to my own fastjet, the version is 3.3.0.

Best
ycwu

Can you try without that link?
For what I see in your log, this is a crash on fastjet, so I'm not able to comment more.
Since it works for me/Rikkert. It is likely that such issue is not present on the fjcore version of fastjet.

Cheers,

Olivier

Hi Olivier:
    I worked in a new unzip directory and without any link to external fastjet, it still crashed. Now there is no error message about fastjet, but still have:

ERROR in OneLOop dilog2_r: j1, j2, r1-r2 -2 0, .00000000000E+00, returning 0
ERROR in OneLOop log1_r: rr,jj = .1000000000000000E+01 -2 , putting jj to 0

Do you have any further suggestion for this problem?

I also have another problem with NLO process in GM NLO model (we've uploaded this to FR website.)
For such a process, we scan the parameter space to get the NLO CS, for most parameter points, there is no problem. But for few of them, it also crashed, and I looked into some log file, find following message:

 ERROR #39 in genps_fks.f 19359960.447059736 19359960.447059724
 ERROR: INTEGRAL APPEARS TO BE ZERO.
 TRIED 100352 PS POINTS AND ONLY 0 GAVE A NON-ZERO INTEGRAND.

According to the result for other points, such point should also give us finite result.

Best
ycwu

Hi Olivier:
   I'm providing more info:

For those points went into problem, if I tune a little bit some parameters in the parameter card, it runs smoothly without any problem.

Hello,

For the problems related to the computation of the partial width for higgs to b-bbar+jet, what is the mass of the b-quark, and what jet-definition are you using for the (light) jet?

Best,
Rikkert

Hi Rikkert:
    For h > b b~ j , the definition of jet is :

define j = g u c d s u~ c~ d~ s~

and in the parameter card, mass for u, c, d, s, are all set to 0, and the bottom mass is 4.7 GeV.

Thanks!

ycwu

Hi,

Thanks. With jet definition I mean the jet algorithm, minimum transverse momentum cut and allowed rapidity range. What are you using for those?

Best,
Rikkert

Hi Rikkert:
    Thanks! I didn't notice that in the run_card there is a section concerning the jet definition. Previously I just ran with default setting, which is K_T and 0 for pt minimum and no cut for rapidity range. After I change the pt minimum to a non-zero value, no more crash. Thanks

best
ycwu