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Literatur

Latex

Latex/KOMA Ref-Sheet

KOMA Docs

AUCTeX

Modular Documents

Feynman Rules

Siegert Vorlesung

CLOCK: [2020-03-18 Wed 10:57]–[2020-03-18 Wed 11:20] => 0:23

Particle Physics

Thomson

CLOCK: [2020-03-18 Wed 16:32]–[2020-03-18 Wed 21:01] => 4:29 CLOCK: [2020-03-18 Wed 11:20]–[2020-03-18 Wed 14:21] => 3:01

Rivet

Monte Carlo

PDFs

Pseudo Rapidity

Sherpa

Aufgaben

Erste Aufgabenp

CLOCK: [2020-03-20 Fri 09:30]

Mail von Siegert

CLOCK: [2020-03-19 Thu 15:21]–[2020-03-19 Thu 17:25] => 2:04 CLOCK: [2020-03-19 Thu 10:05]–[2020-03-19 Thu 11:56] => 1:51

Hi Valentin,

alles klar. Das Formular machen wir dann einfach im Nachhinein und datieren es zurueck.

Dann wuerde ich zur Einarbeitung vorschlagen, Du schaust Dir mal meinen Aufschrieb zu Feynman-Regeln und der |M|^2-Berechnung aus der Vorlesung an, Kapitel 4.3 und 4.4 hier:

http://fsiegert.web.cern.ch/fsiegert/tmp/tk-vorlesung.pdf

Versuch das erstmal fuer den gezeigten Prozess nachzuvollziehen, und schau dann, ob Du folgende Uebungsaufgaben aus meinem Kurs kannst: 4.1 4.2 5.1 5.2 5.3 https://bildungsportal.sachsen.de/opal/auth/RepositoryEntry/11966152704/CourseNode/92162447560998

Wenn Du konzeptionell oder rechnerisch irgendwo haengen bleibst, reden wir (Skype/Vidyo/Zoom/…), damit ich einzelnes nochmal naeher erlaeutern kann. Wenn Du damit durch bist, kann ich Dir die Musterloesungen zur Verfuegung stellen und du schaust nochmal genauer, ob noch irgendwas unklar ist.

Dann kannst Du mal qq->yy rechnen.

Klingt das OK fuer den Start?

Viele Gruesse, Frank

Berechnung qq -> γγ

  • 4 Anlaeufe :). Idiotischerweise 4-Vektor negiert
  • letzter Anlauf mit Casimir Trick erfolgreich

  • gute tricks:

    • γ auf z Achse
    • Symmetrien Beachten -> spart die Haelfte beim umdrehen der Spins
  • Vollstaendigkeitsrelation von pol. Vektoren in Form: Completeness Pol. Vectors

Vergleich mit Sherpa

Monte Carlo Methods

DONE Check Statistics

  • 100 mal…. 67, check with random seed
  • error bars in histtype

DONE Variablen Trafo geschickt waehlen.

  • stratified sampling, vegas
TODO Something fishy about that variance estimate in vegas!!!
  • overesimate even stronger if evaluation point number increased

DONE Sherpa + Rivet

  • analyse + histogramme
  • Analysis: MC_DIPHOTON, analysis reference
  • sherpa configure: ../configure --enable-rivet=/usr/bin/rivet --prefix=/usr --enable-hepmc2=/usr
  • manual

Parton Density functions

Phaeono

pT sortieren

TODO Shower

  • pT only works with showers
  • remnants of proton create showers -> without fragmentation: no hadrons
  • can create more photons

  • limited -> conserves m_yy

TODO Fragmentation,

TODO MI

  • multiple partons interact, create showers etc

Clock Table

Headline Time
Total time 7:53
Literatur 7:53
  Feynman Rules 0:23
  Particle Physics 7:30
Clock summary at [2020-03-18 Wed 21:01]

Fragen

Lorentz Invar. Matrixelement

  • Ich stand ganz schoen auf dem Schlauch: Lorentz Invar = selbe Form in allen BS (muss nicht unb. konst bei LT sein), lorentzskalarfeld

Impulserhaltung aus dem Gefuehl… (ohne deltas) ok?

Normierung Photonenfeld?

Globaler Spin bei pol. Vektoren?

Spin nicht erhalten?

Abweichungen im vergeich weiter diskutieren?

Flavours im Proton

Sind quark verhaeltnisse in PDF enthalten (2:1 fuer proton)

beide finalstate photonen behalten?

PDF members

Sensitivity detectors cite! -> separation from beam

was fuer eine pdf ist das NNPDF31lo

four mom. conservation errors

Warum Veto nur fuer MUONS

  • ich habe auch photons gevetoed

Initial und finals state radiation?

MPI

  • nur QCD -> wichtigste prozesse modelliert

  • The Jimmy model stops here, considering only hard events, and so it can only be applied to underlying event.

    • doesn't the mpi contain soft inclusive physics

Jet algos

  • what are jet xs? -> particles jets as legs
  • why ist double counting a problem -> in exact calculation -> same diagramm
  • IS radiation: all partons?

Soft Inclusive

  • wtf are those processes

what does inclusive mean

Normalize to XS

y axis label for normalized histos

DONE PDF cannot be derived: in principle?

DONE still compatible?

DONE cite atlas paper (analysis?)

DONE call it distribution?

DONE diphoton caps?

DONE do remnants radiate?

TODO ask about nlo emissions

Work Log

18.03

  • habe mich in manche konzeptionelle Dinge ziemlich verrannt!

Todo

TODO lab xs kuerzen

TODO shower scale anpassen

DONE effekt shower und kperp

DONE y-axis a.u.!

DONE mean, var einzeichnen

DONE Variance of vegas weighted f!

DONE look at xs plot -> they seem different

DONE take new sample: still bias?

DONE umnumerieren

Observations

XS

  • highest LO: isolation easiest

    • dispite nothing being pushed into the cuts
  • others pretty much in sequence: the more effects the lower -> isolation
  • hadronisation improves isolation: less noise
  • MI: more noise

Azimuthal Angle

  • 0 for basic
  • converge at large angle -> expected
  • smaller angle with PS but also last bin smaller
  • all otherssimilar, at lower -> MI/Hadrons (copatible) a little higher
  • in general flattens out

Cos Θ

  • familiar, a little less steep
  • apart from total xs differences: rather compatible

η

  • again, a little less steep: enhancement in center through pT
  • shapewise compatible
  • long drop to MI visible

Invariant Mass

  • now c.m. Energies lower than cut pass: pT

  • lo+ps: enhanced towards higher cm enegies (at lowers compat)

    • due to higher pT boosts favored + higher xs
  • steep decile: pdf
  • minimum around 1GeV -> massless limit ~OK

Scattering Angle

  • shapewise similar -> bit flatter than basic, more center
  • cuts force 0 at extremes (pT invariant in z boosts)

Scattering Angle in CS Frame

  • does not go to zero due to finite pT

  • at extreme angles: PS+pT enhanced: smaller pT also included

    • weak effect, not 2 sigma!
    • would need more events
  • enhancement in center gone (normalized!) -> symmetry restored!
  • greates differentce in low scat, angle regeime CUTS+Normalization
  • hard process not really affected through higher order effects (apart from kinematics!)

pT leading

  • shifted towards higher pT
  • at pT > 1GeV compatible
  • pT < 1GeV

pT subleading

  • apart from total xs shift: not much difference
  • interesting because one would espect enhancement at lower pT, which is hardly visible

TODO check that with normalized plots

  • visible but minute!
  • culled by cuts

Azimuthal Angle

  • as expected, a lot of weight at low angles
  • LO+PS: greater weight at higher pT -> bigger shifts in angle
  • rotation symmetry: boos in each direction equally likely -> similar shapse
  • BASIC always back to back
  • > ps+pt -> greater weight at lower pT so more often back to back

TODO total pT

  • steep drop after maximum in the order of 1GeV

  • in region around <2 GEV splitt: Jet momemnta dropp off (resummation, sudakov)

    • primordial k_perp mean .8 GeV enhances lower regions

  • MI oddly enhanced at very low pT: more PS from other interactions -> less on the hard process quarks?

    • no interleaving in SHERPA
    • minimizes rel. transv. mom or shuffling if no mpi
    • maybe isolation better for low pT ?

overall

  • everything more than PS+PT: isolation
  • biggest effect is the jet kick, photons are no qcd particles and not touched after hard process
  • no em radiation activated: would add more noise, here no additional photons

426 .. ref for CSS 433/436 .. refs 443 .. to zu viel 448 .. azimuthal 451 .. verb zu viel 452 .. collinear

kick -> recoil, klarer, momentum conservation am anfang! 481/6708

primordial pT, erklaeren fermi motion

figs umsortieren

484 .. often off the orderd -> of

ok .. pT > 1e-1 MI schwer zu sagen, uninteressant, weglassen, nicht messbar

discuss -> parton shower collinear limes naeherung (falling off steeply), kein grosses pT, keine gute naeherung in > 10 GeV

nontrivial feater of .. modeling

492 .. back to back preference -> nur folge der nlo unterdrueck

was ist LO threshhold, durch pT cuts ist keine c.m. energy -> inv mass

very rare -> higher order (α_s kleiner) harte qcd kosten!

inv m LO+PS nicht verschieben 510 .. 511

524 .. welcher effekt

bigger picture .. lo bild -> geeignet, auch einfache betroffen (auch am anfang) uberall auswirkung

outlook very simple, nlo ME verwenden, fragmentation aus parton (dijet), neue photon iso + viel mehr

chi^2 test