The Smoking Gun of BNV Colour Topologies and String Hadronization - PowerPoint PPT Presentation

ECFA LC Workshop 2003 The Smoking Gun of BNV Colour Topologies and String Hadronization in Baryon Number Violating Supersymmetry P . Skands (speaker) & T. Sjöstrand, Lund University. Nucl.Phys.B659:243,2003 ; hep-ph/0209199 The Smoking Gun of Baryon Number Violation, P . Skands – p.1/18

Overview 1. BNV SUSY: Quick Intro. 2. BNV SUSY in PYTHIA. 3. Colour topologies and hadronization. 4. Properties and predictions. 5. Conclusion. The Smoking Gun of Baryon Number Violation, P . Skands – p.2/18

✝ ✞ � ✁ ✂ ✂ ✁ ✄☎ ✆ ✟ ☎ ✆ BNV SUSY: Quick Introduction Most general (MSSM) superpotential: But + makes bad cocktail! The Smoking Gun of Baryon Number Violation, P . Skands – p.3/18

✞ ☎ ✁ ✟ ✂ ✄ ✟ ✞ � ✆ ✝ ✆ ✄☎ ✁ ✂ ✂ ✁ � BNV SUSY: Quick Introduction Most general (MSSM) superpotential: But + makes bad cocktail! To save proton, , , or cons. imposed. CDM candidate, but no deep motivation. and more robust with higher dimension operators. No clear-cut answer. The Smoking Gun of Baryon Number Violation, P . Skands – p.3/18

✟ ✝ ✌✍ ✝ ☞ ☛ ✡ ✞ ✟ ☎ ✠ ✞ ✄ ✠ ✂ ✆ ✠ ✟ ✞ ✝ ✆ ☎ ✂✄ ✁ ✁ � � ✆ ✄☎ ✎ BNV SUSY: Quick Introduction Baryon Number Violation in Superpotential: ( = colour, = generation) Couplings between chiral multiplets. Sfermions: 2-body decays. Gauginos/Higgsinos: 3-body decays (via sfermion resonances). ‘baryonic’ colour flow. (This talk is not about BNV in production.) The Smoking Gun of Baryon Number Violation, P . Skands – p.4/18

Overview 1. BNV SUSY: Quick Intro. 2. BNV SUSY in PYTHIA. 3. Colour topologies and hadronization. 4. Properties and predictions. 5. Conclusion. The Smoking Gun of Baryon Number Violation, P . Skands – p.5/18

✓ ✁ ✞ ✌ ☎ ✍ ☎ ✎ ✌ ☎ ✌ ✞ ✁ ☞ ✞ ☞ ✌ ✞ ✍ ☎ ✎ ✌ ✝ ☎ ✌ ✝ ☎ ✍ ✝ ✁ ☛ ✎ ✝ � � ✁ ✁ ✁ ✖ ✂ ✕ ✍ ✍ ✁ ✌ ✌ ☎ ✍ ✎ ✎ ✄ ✞ ✌ ✁ ✝ ☎ ✍ ✝ ☎ ✎ ☎ ☎ BNV SUSY in PYTHIA UDD : 200 new decay chanels ✄✆☎ , , ✄✡✠ ✄✡✔ ✝✟✞ ✍✏✎✒✑ ✎✒✑ ✎✒✑ ✎✒✑ , ✄✡✠ Partial widths: tree-level ME’s, massive and . Momentum distributions: isotropic 3-body phase space (good approx. when intermediate propagators way off shell, worse when only slightly off shell). Final state parton multiplicity increased by subsequent showers. Only MSSM pair production included. The Smoking Gun of Baryon Number Violation, P . Skands – p.6/18

Overview 1. BNV SUSY: Quick Intro. 2. BNV SUSY in PYTHIA. 3. Colour topologies and hadronization. 4. Properties and predictions. 5. Conclusion. The Smoking Gun of Baryon Number Violation, P . Skands – p.7/18

✁ ✁ ☎ ✁ � ☛ ✁ ✁ ✝ ✁ ✄ ✁ ✂ ✁ ✝ Colour topologies ‘Ordinary’ colour topology ‘Baryonic’ colour topology (e.g. ): (e.g. ): How does such a system fragment? Could a Baryon excess be observed? The Smoking Gun of Baryon Number Violation, P . Skands – p.8/18

� Colour topologies and hadronization Fundamental properties of QCD vacuum suggest string picture still applicable. String energy minimization + dipole pic- ture picture of 3 string pieces meet- ing at a ‘string junction’. (Warning: This picture was drawn in a “pedagogical projection” where distances close to the center are greatly exaggerated!) The Smoking Gun of Baryon Number Violation, P . Skands – p.9/18

✠ ☎ ✌ ✌ ✟ � ✓ ✟ ✠ ✡ � ✂ ✂ ☛☞ ✔ ✘ � ✂ � ✁ ✘ ✜ ✙ ✢ ✡ The Smoking gun! The movement of the string junction is crucial, it is the smoke of the BNV gun! A junction is a topological feature of the string confinement field: � ✁� . Each string piece acts on the other two with a constant force, . ✄✆☎✞✝ in junction rest frame (JRF) the angle is 120 between the string pieces. Or better, ‘pull vectors’ lie at 120 : ✕✗✖ ✙✛✚ ✂ ✎✍ ✏✒✑ (since soft gluons ‘eaten’ by string) The Smoking Gun of Baryon Number Violation, P . Skands – p.10/18

� ✍ ✗ ✗ ✔ � ☎ � � ✞ � Fragmentation The movement of the string junction is crucial, it is the smoke of the BNV gun! ✑✓✒ �✏✎ �✌✎ �✆✍ �✝✄ �✂✄ �✂✁ �✆✞ �✆✟ �✆✡ ☛✌☞ �✝✁ �✠✟ �✠✡ �✆☎ �✌✔ ✑✖✕ First 2 pieces fragmented outwards–in, junction baryon formed around junction, last string piece fragmented as ordinary string. The Smoking Gun of Baryon Number Violation, P . Skands – p.11/18

✕ ✁ ✕ ☞ ✁ ✄ ☞ ☎ ✁ ✒ ☎ ✁ ✒ Intermezzo: more complicated topologies Stop pair production at an LC: a) 2 J baryons �✂✁ b) No J baryons �✂✁ Select: a) or b) based on string length measure. The Smoking Gun of Baryon Number Violation, P . Skands – p.12/18

✕ ✁ ✁ ☞ ✒ ✄ ☞ ☎ ✁ ✒ ☎ ✁ ✕ Intermezzo: more complicated topologies Stop pair production at an LC: a) 2 J baryons �✂✁ b) No J baryons �✂✁ m stop = 50 GeV Pythia 6210 1 P - perturbative breakup JJ 2 junction baryons 0.8 Select: a) or b) 0.6 based on string length measure. - string JJ 0.4 2 junction baryons 0.2 - annihilation JJ No junction baryons 0 1 2 3 4 5 6 γ stop The Smoking Gun of Baryon Number Violation, P . Skands – p.12/18

✄ ✏ Intermezzo: more complicated topologies Colour flow in gluino decays: ✄✆✝ �✂✁ ✄✆☎ Selected according to (off–shell) resonance propagators. The Smoking Gun of Baryon Number Violation, P . Skands – p.13/18

Overview 1. BNV SUSY: Quick Intro. 2. BNV SUSY in PYTHIA. 3. Colour topologies and hadronization. 4. Properties and predictions. 5. Conclusion. The Smoking Gun of Baryon Number Violation, P . Skands – p.14/18

Properties and Predictions Dependence on Fragmentation assumptions: ~ χ 1 → u d s m χ = 96 GeV Pythia 6209 10 dN/dp CM Default Fragmentation: Least Energetic Last Junction Pull: E norm → ∞ Junction Pull: E norm = 0.5 Junction Pull: CM Energies 1 Junction Rest Frame = String CM Junction Baryons Primary Hadrons -1 10 < N > DEF = 21.63 < N > LEL = 21.88 < N > → ∞ = 21.58 < N > 0.5 = 21.67 < N > CME = 21.74 -2 < N > SCM = 21.88 10 0 5 10 15 20 p CM [ GeV ] Description is assymmetric but differences are small. The Smoking Gun of Baryon Number Violation, P . Skands – p.15/18

Properties and Predictions Junction fragmentation implies: ~ χ 1 → u d s m χ = 96 GeV dN/dp CM Pythia 6209 - Junction Baryons Pythia 6209 - ″ Ordinary ″ Baryons Herwig 6301 - Junction Baryons Herwig 6301 - ″ Ordinary ″ Baryons -1 10 < N bary > Pythia =3.4 < N bary > Herwig =4.5 -2 10 0 5 10 15 20 p CM [ GeV ] if leading jets are well separated, junction will be slow, and junction baryon will be at low momenta: The Smoking Gun of Baryon Number Violation, P . Skands – p.16/18

Overview 1. BNV SUSY: Quick Intro. 2. BNV SUSY in PYTHIA. 3. Colour topologies and hadronization. 4. Properties and predictions. 5. Conclusion. The Smoking Gun of Baryon Number Violation, P . Skands – p.17/18

Conclusion A model for BNV-SUSY allowing detailed studies available in PYTHIA. Special attention given to the non- perturbative aspects. Hadronization based on physical picture shows new aspects. Generic prediction (apologies to particle ID people!) : The smoking Gun — slow baryons. Junction fragmentation also used for multi- ple interactions, see friday morning talk in QCD/Generators session. The Smoking Gun of Baryon Number Violation, P . Skands – p.18/18