Changes between Version 9 and Version 10 of WikiStart


Ignore:
Timestamp:
Jun 24, 2013, 2:04:21 PM (12 years ago)
Author:
Gustavo Gil Da Silveira
Comment:

correcting typos and adding more details: changes in the original code, variables from interacting particles

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  • WikiStart

    v9 v10  
    77There are currently two versions of this Monte Carlo generator (which can be found [[http://cmssw.cvs.cern.ch/cgi-bin/cmssw.cgi/UserCode/Forthomme/lpair/|here]]) studying two different kind of processes:
    88
    9 1. `DESY` version: developed for electron-proton collisions in HERA, with built-in option for proton-proton collisions as "test". This version allows one to study elastic and inelastic (single dissociation) processes for the production of dileptons; and
     91. `DESY` version: developed for electron-proton collisions in HERA, with built-in option for proton-proton collisions as //test//. This version allows one to study elastic and inelastic (single dissociation) processes for the production of dileptons; and
    1010
    11112. `CDF` version: improved version which allows one to study elastic and double dissociation processes with more phase-space cuts available.
    1212
    13 In this current analysis, we focus in the exclusive dimuon production, gamma-gamma -> mu+ mu-, in inelastic collisions (single dissociation). LPAIR makes use of the [[http://home.thep.lu.se/~torbjorn/pythiaaux/introduction.html|JetSet]] library present in [[http://home.thep.lu.se/~torbjorn/pythiaaux/present.html|Pythia]] in order to perform the hadronization of the proton remnants.
     13In this current analysis, we focus in the exclusive dimuon production, γγ -> μ^+^μ^-^, in inelastic collisions (single dissociation). LPAIR makes use of the [[http://home.thep.lu.se/~torbjorn/pythiaaux/introduction.html|JetSet]] library present in [[http://home.thep.lu.se/~torbjorn/pythiaaux/present.html|Pythia]] in order to perform the hadronization of the proton remnants.
    1414
    1515The built-in options for proton dissociation in LPAIR make use of two parametrizations for the parton densities inside the proton, namely:
    … …  
    2828== Set up ==
    2929
     30=== Code changes ===
     31
     32A few changes are made in the code to have access to more information about the particles in the event sample produced in `LPAIR`, especially to distinguish the muons from the exclusive production from the remnants from the proton break up. Then, two changes are made in the file //ilpair-cms-pp.f// in order to store information from `JetSet` in the `HBOOK` files:
     33
     341. particle status code, //ks//, at line 246; and
     35
     362. particle parentage, //icode//, at line 248.
     37
     38Also, taking advantage for the fact that `LPAIR` performs the theoretical calculation in terms of Q^2^, the p,,T,, cut is internally applied by means of a Q^2^ cut in file //peripp.f// at line 29.
     39
     40
    3041=== Event samples ===
    3142
    … …  
    3950The built-in PDFs in `LPAIR` are replaced by two paramatrizations for the parton densities:
    4051
    41 1. Gluck-Reya-Vogt (`GRV`) [[http://dx.doi.org/10.1007/s100520050289|Eur.Phys.J. C5 (1998) 461-470]]
     521. Glueck-Reya-Vogt (`GRV`) [[http://dx.doi.org/10.1007/s100520050289|Eur.Phys.J. C5 (1998) 461-470]]: version `GRV95` at leading order (`LO`) in α,,s,,.
    4253{{{
    4354* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
    … …  
    7384}}}
    7485
    75 2. Parametrization by Fiore et al.
    76 
    77 To be added
     862. Parametrization by Fiore et al [[http://epja.epj.org/articles/epja/abs/2002/10/100500505/100500505.html|Eur. Phys. J. A 15, 505-515 (2002)]].
     87
     88>**Abstract**: An explicit model realizing parton-hadron duality and fitting the data is suggested. Complex nonlinear Regge trajectories are important ingredients of the
     89>model. The inclusion of ∆ and N^∗^ trajectories should account for all resonances in the direct channel. The exotic trajectory is responsible for the smooth background.
     90
     91This parametrization is meant to fit the data for the low Q^2^ region, reproducing the resonances of low-mass mesons. The figure below shows the distribution F,,2,, vs. `x` for Q^2^ = 0.5 GeV^2^:
     92
     93[[Image(source:/trunk/plots/FIORE_F2_x.png, 500px)]]
     94
     95=== Variables ===
     96
     97The final-state kinematics is used to make the distributions in terms of the variables of the interacting particles, like the photon virtuality, Q^2^, by:
     98
     99> Q^2^ = [P,,p,,(E)-p,,rem,,(E)]^2^-[P,,p,,(x)-p,,rem,,(x)]^2^-[P,,p,,(y)-p,,rem,,(y)]^2^-[P,,p,,(z)-p,,rem,,(z)]^2^
     100
     101and the momentum fraction of the proton carried by the photon, x, by
     102
     103> x = Q^2^/(M,,X,,^2^-M,,p,,^2^+Q^2^),
     104
     105with ξ given by
     106
     107> ξ=`log`,,10,,(x)
     108
    78109
    79110== Results ==
    … …  
    145176In order to have results closer to the observed results in the data analysis, event samples are produced within the experimental acceptance used for at trigger level in CMS:
    146177
    147 1. p,,T,,(mu) < 3 GeV;
    148 
    149 2. |η(mu)| < 2.4.
    150 
    151 3. p,,T,,(mu^+^mu^-^) > 10 GeV.
    152 
    153 The first set of plots shows the events restricted to a hadronic system with mass lower than **100 GeV**, while the second consider masses up to 300 GeV.
     1781. p,,T,,(μ) > 10. GeV;
     179
     1802. |η(μ)| < 2.4.
     181
     1823. M(μ^+^μ^-^) > 10. GeV.
     183
     184The first set of plots shows the events restricted to a hadronic system with mass lower than **100 GeV**, while the second consider masses up to **300 GeV**.
    154185
    155186||||||= **1M events** =||
    … …  
    215246The comparisons are performed by, first, the ratio between the distributions with and without experimental acceptance and, next, the `SURI-YENNIE` and `GRV` parametrizations.
    216247
     248
    217249||||||= **1M events** =||
    218250||||||= **M,,X,, < 300 GeV** =||
    219251||= **`SURI-YENNIE`** =||= **`GRV`** =||
    220 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_etapair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_etapair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    221 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_etarem_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_etarem_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    222 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_invm_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_invm_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    223 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_invmlarge_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_invmlarge_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    224 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_mx_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_mx_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    225 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_mx_zoom_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_mx_zoom_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||
    226 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_mx_zoom2_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_mx_zoom2_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    227 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_mx2_zoom_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_mx2_zoom_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    228 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_mx2_zoom2_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_mx2_zoom2_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    229 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_ptpair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_ptpair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    230 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_ptpairlarge_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_ptpairlarge_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    231 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_Q2_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_Q2_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    232 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_Q2large_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_Q2large_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    233 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_x_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_x_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    234 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_xi_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_xi_Q2_nocut_exp_accp_MXmax_300.png, 500px)]]  ||
    235 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_xilog_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_xilog_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||
    236 || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI:cuts-nocuts_1Mevt_ypair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||  [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_GRV:cuts-nocuts_1Mevt_ypair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||
     252|||| to be added ||
     253
    237254
    238255||||||= **1M events** =||
    … …  
    245262|| [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI-GRV_1Mevt_Q2large_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI-GRV_1Mevt_x_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI-GRV_1Mevt_xi_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||
    246263|| [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI-GRV_1Mevt_xilog_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] || [[Image(source:/trunk/plots/exp_cuts/ratio_MXmax_300GeV/RATIO_SURI-GRV_1Mevt_ypair_Q2_nocut_exp_accp_MXmax_300.png, 500px)]] ||||
     264
     265
     266=== LPAIR++ ===
     267
     268to be added