Herwig++ in Gauss Philip Ilten University College Dublin Bucharest - PowerPoint PPT Presentation

Herwig++ in Gauss Philip Ilten University College Dublin Bucharest MC Workshop November 23, 2012 Ilten (UCD) Herwig++ in Gauss November 23, 2012 1 / 15

Introduction : Overview Overview ❼ Herwig++ : ❼ Powheg weighting NLO matrix elements: ❼ Higgs production ❼ vector boson pair production q ′ → W → f ¯ f ′ , q ¯ q → γ/Z → f ¯ ❼ q ¯ f ❼ MatchBox NLO framework (experimental) ❼ full polarization mechanism ❼ sophisticated decay models ❼ cluster hadronization (better for heavy flavor) ❼ different ISR and FSR methods from Pythia ❼ different underlying event and MPI ❼ Resources: ❼ Herwig++: Physics and Technical Aspects ❼ Herwig++ Physics and Manual ❼ Herwig++ API ❼ ThePEG API Ilten (UCD) Herwig++ in Gauss November 23, 2012 2 / 15

Introduction : Matrix Elements LO Matrix Elements Name Process MEDISCC charged current deep inelastic scattering MEDISNC neutral current deep inelastic scat- tering MEMinBias simple color singlet exchange MEQCD2to2 pp → X 1 + X 2 gg → f ¯ MEgg2ff f pp → b ¯ b/t ¯ MEHeavyQuark t MEGammaGamma pp → γγ MEGammaJet pp → γ + jet MEPP2VGamma pp → W/Z + γ MEPP2VV pp → WW/ZZ/WZ MEWJet pp → W + jet MEZJet pp → Z + jet MEgg2WW gg → WW q → W → f ¯ q ¯ f MEqq2W2ff q → γ ∗ /Z → f ¯ q ¯ f MEqq2gZ2ff Ilten (UCD) Herwig++ in Gauss November 23, 2012 3 / 15

Introduction : Matrix Elements LO Higgs Matrix Elements Name Process gg/qg → H MEHiggs pp → H + jet MEHiggsJet pp → WW/ZZ → H MEPP2HiggsVBF pp → WH MEPP2WH pp → ZH MEPP2ZH pp → b ¯ MEPP2bbbarH bH pp → t ¯ MEPP2ttbarH tH Ilten (UCD) Herwig++ in Gauss November 23, 2012 4 / 15

Introduction : Matrix Elements NLO Matrix Elements Name Process gg/gq → H PowhegMEHiggs pp → WW/ZZ → H PowhegMEPP2HiggsVBF pp → WW/ZZ/WZ PowhegMEPP2VV pp → WH PowhegMEPP2WH pp → ZH PowhegMEPP2ZH q → W → f ¯ PowhegMEqq2W2ff q ¯ f q → γ ∗ /Z → f ¯ PowhegMEqq2gZ2ff q ¯ f Ilten (UCD) Herwig++ in Gauss November 23, 2012 5 / 15

Introduction : Polarization Polarization ρ j j = ρ 1 1 ρ 2 2 λ j λ ′ κ 1 κ ′ κ 2 κ ′ 2 × M κ 1 κ 2 ; λ 1 ...λ n M ∗ κ ′ 1 κ ′ 2 ; λ ′ 1 ...λ ′ n Y D k × λ k λ ′ k k � = j 16000 Z H 14000 0 M λ 0 ; λ 1 ...λ n M ∗ W decay = ρ λ 0 λ ′ W 3 λ ′ 0 ; λ ′ 1 ...λ ′ H ± n 12000 Y D k × λ k λ ′ N events 10000 k k =1 ,n 8000 0 = M λ 0 ; λ 1 ...λ n M ∗ D λ 0 λ ′ 6000 5 λ ′ 0 ; λ ′ 1 ...λ ′ n 4000 Y D l × λ l λ ′ l 2000 l =1 ,n 0 0 0.2 0.4 0.6 0.8 1 decay ν τ 2 E π − / √ s initial interaction ¯ ν e W − τ − e + e − τ + γ u e − ¯ W + d decay ν τ ¯ Ilten (UCD) Herwig++ in Gauss November 23, 2012 6 / 15

Introduction : Decays Decays q ′ → W − → τ − → ν τ π 0 π − π − π + q ′ → W − → τ − → ν τ π − π + K − q ′ → W − → τ − → ν τ π − π + K − q ¯ q ¯ q ¯ 3 10 80000 120 Pythia 8 Pythia 8 70000 Herwig++ Herwig++ Tauola 100 Tauola 60000 80 50000 N events N events 40000 60 30000 40 20000 20 10000 0 0 3 3 -3 -3 0.8 1 1.2 1.4 1.6 1.8 0.4 0.6 0.8 1 1.2 1.4 1.6 m π − π + K − [GeV /c 2 ] m π 0 π − π + [GeV /c 2 ] Ilten (UCD) Herwig++ in Gauss November 23, 2012 7 / 15

Implementation : Gauss Package Gauss Package ❼ cmt ❼ Gauss/Gen/LbHerwigpp ❼ requirements - CMT # = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = configuration u s e G e n e r a t o r s v ✯ G e n u s e h e r w i g ++ v ✯ → ❼ src/component L C G _ G e n e r a t o r s I n t e r f a c e s u s e t h e p e g v ✯ → ❼ HerwigppProduction - L C G _ G e n e r a t o r s I n t e r f a c e s actual production source # = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ❼ src/Lib m a c r o h e r w i g ++ _ n a t i v e _ v e r s i o n " → 2 . 5 . 1 " " → ❼ GaudiRandomForHerwigpp m a c r o t h e p e g _ n a t i v e _ v e r s i o n 1 . 7 . 1 " - legacy random number # = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = interface c o m p o n e n t / ✯ . c p p l i b r a r y L b H e r w i g p p # = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = → a p p l y _ p a t t e r n c o m p o n e n t _ l i b r a r y l i b r a r y = L b H e r w i g p p Ilten (UCD) Herwig++ in Gauss November 23, 2012 8 / 15

Implementation : Methods Methods ❼ initialize ❼ initializeGenerator ❼ finalize ❼ generateEvent ❼ toHepMC ❼ setStable ❼ updateParticleProperties ❼ turnOnFragmentation ❼ turnOffFragmentation ❼ hadronize ❼ savePartonEvent ❼ retrievePartonEvent ❼ printRunningConditions ❼ isSpecialParticle ❼ setupForcedFragmentation Ilten (UCD) Herwig++ in Gauss November 23, 2012 9 / 15

Implementation : Random Numbers Random Numbers ❼ No direct interface with Herwig++ ( GaudiRandomForHerwigpp ). ❼ Clear and reset ThePeg random number generator per event. ❼ Set the seed from Gauss . // Set the random seed . r n d = m _ r a n d o m . s h o o t ( ) I N T _ M A X ; i n t ✯ // Flush the Herwig++ random g e n e r a t o r . m _ h e r w i g p p − > a c c e s s R a n d o m ( ) − > f l u s h ( ) ; // Set the Herwig++ random g e n e r a t o r seed . m _ h e r w i g p p − > a c c e s s R a n d o m ( ) − > s e t S e e d ( r n d ) ; Ilten (UCD) Herwig++ in Gauss November 23, 2012 10 / 15

Implementation : Defaults Defaults ❼ Use min-bias simple color singlet exchange. ❼ Not tuned! ❼ Use Herwig++ for min-bias, pile-up? " i n s e r t / H e r w i g / M a t r i x E l e m e n t s / S i m p l e Q C D : M a t r i x E l e m e n t s [ 0 ] / H e r w i g / → M a t r i x E l e m e n t s / M E M i n B i a s " " s e t / H e r w i g / C u t s / J e t K t C u t : M i n K T 0 . 0 * G e V " " s e t / H e r w i g / C u t s / Q C D C u t s : M H a t M i n 0 . 0 * G e V " " s e t / H e r w i g / C u t s / Q C D C u t s : X 1 M i n 0 . 0 5 5 " " s e t / H e r w i g / C u t s / Q C D C u t s : X 2 M i n 0 . 0 5 5 " " s e t / H e r w i g / U n d e r l y i n g E v e n t / M P I H a n d l e r : I d e n t i c a l T o U E 0 " " s e t / H e r w i g / U n d e r l y i n g E v e n t / M P I H a n d l e r : s o f t I n t Y e s " " s e t / H e r w i g / U n d e r l y i n g E v e n t / M P I H a n d l e r : t w o C o m p Y e s " " s e t / H e r w i g / U n d e r l y i n g E v e n t / M P I H a n d l e r : D L m o d e 3 " Ilten (UCD) Herwig++ in Gauss November 23, 2012 11 / 15

Validation : Configuration Configuration ❼ Locally generated NLO Powheg f ¯ f → Z → µ − µ + . ❼ Full simulation, digitization, and reconstruction. ❼ Options file: G e n e r a t i o n . E v e n t T y p e = 42122011; G e n e r a t i o n . P i l e U p T o o l = ✬ F i x e d L u m i n o s i t y ✬ ; G e n e r a t i o n . D e c a y T o o l = ✬ ✬ ; G e n e r a t i o n . S a m p l e G e n e r a t i o n T o o l = ✬ S p e c i a l ✬ ; G e n e r a t i o n . S p e c i a l . C u t T o o l = ✬ ✬ ; G e n e r a t i o n . S p e c i a l . D e c a y T o o l = ✬ ✬ ; G e n e r a t i o n . S p e c i a l . P r o d u c t i o n T o o l = ✬ H e r w i g p p P r o d u c t i o n ✬ ; G e n e r a t i o n . S p e c i a l . H e r w i g p p P r o d u c t i o n . O u t p u t L e v e l = 2 ; G e n e r a t i o n . S p e c i a l . H e r w i g p p P r o d u c t i o n . C o l l i d i n g B e a m s . B e a m M o m e n t u m = → 3500000; G e n e r a t i o n . S p e c i a l . H e r w i g p p P r o d u c t i o n . C o m m a n d s += { p r o d u c t i o n . ✬ , ✬ # E n a b l e N L O Z b o s o n / H e r w i g / M a t r i x E l e m e n t s / ✬ , ✬ cd Z ✬ , ✬ s e t P o w h e g M E q q 2 g Z 2 f f : G a m m a Z M u o n ✬ , ✬ s e t P o w h e g M E q q 2 g Z 2 f f : P r o c e s s P o w h e g M E q q 2 g Z 2 f f ✬ , ✬ i n s e r t S i m p l e Q C D : M a t r i x E l e m e n t s [ 0 ] c u t s . ✬ , ✬ # S e t 2 . 0 ✬ , ✬ s e t / H e r w i g / C u t s / L e p t o n K t C u t : M i n E t a 5 . 0 ✬ , ✬ s e t / H e r w i g / C u t s / L e p t o n K t C u t : M a x E t a ✬ s e t / H e r w i g / C u t s / L e p t o n K t C u t : M i n K T 2 0 . 0 * G e V ✬ } ; Ilten (UCD) Herwig++ in Gauss November 23, 2012 12 / 15

Validation : Z Variables Z Variables MC10 MC10 Herwig++ Herwig++ 0.3 0.3 0.25 0.25 0.2 0.2 0.15 0.15 0.1 0.1 0.05 0.05 0 0 60 70 80 90 100 110 120 0 0.5 1 1.5 2 2.5 3 M [GeV] ∆ φ Z MC10 MC10 Herwig++ Herwig++ 0.1 0.12 0.1 0.08 0.08 0.06 0.06 0.04 0.04 0.02 0.02 0 0 2 3 4 5 6 7 8 9 10 0 5 10 15 20 25 30 35 40 45 50 p Z [GeV] η Z T Ilten (UCD) Herwig++ in Gauss November 23, 2012 13 / 15

Validation : µ Variables µ Variables MC10 MC10 Herwig++ Herwig++ 0.14 0.14 0.12 0.12 0.1 0.1 0.08 0.08 0.06 0.06 0.04 0.04 0.02 0.02 0 0 20 30 40 50 60 70 80 0 10 20 30 40 50 60 µ µ p 1 [GeV] p 2 [GeV] T T MC10 MC10 Herwig++ Herwig++ 0.45 0.4 0.4 0.35 0.35 0.3 0.3 0.25 0.25 0.2 0.2 0.15 0.15 0.1 0.1 0.05 0.05 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 isolation [GeV] isolation [GeV] µ µ 1 2 Ilten (UCD) Herwig++ in Gauss November 23, 2012 14 / 15