JUAN CARDENAS - PHYSICS MAJORNIGMS RISE SCHOLAR

Juan CardenasCSUDH

Evidence for Λp Elastic Scattering in the CLAS Detector

Cal State University, Dominguez Hills Hadronic Structure Laboratory

Mentor: Dr. John Price

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OUTLINE

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Λp Scattering Motivation

Previous DataData mining g12 SkimmingData Analysis MethodsResultsFuture Plans

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Proton Neutron

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GOAL OF NUCLEAR PHYSICS

Feb 12th 2015 Juan Cardenas

Feb 12th 2015 Juan Cardenas

PROTON STUDY

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γp→γpProton interacts via EM + Strong forceK+, π+, Ko, π-

p, Λ, Ξ But.. other particles

don’t live long..

Κ Λ

Ξ Σ

π

n

p

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Cross section of pX

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PHYSICAL EXPERIMENT

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Data mining on g121 of 2 with long target 40cm LH2

Energy 3.6 – 5.4GeVWell suitedLarge acceptance

(Spherical shape)

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EVENT BREAKDOWN

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pγ

πpΛpKΛ

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Data Skim/Data Selectiono Look for 2

protonso Apparent

Baryon # violation = Rescattering Signal

o 126TB -> 17GB • Reconstruct

scattered Λ

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Apparent Baryon Number Violation

126 TB

17GB

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LAMBDA RECONSTRUCTION

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P

π

Λ

P

X

ΛX

Λ mass = 1.115 GeV

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MISSING MASS AT LAMBDA MASS!

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Implications1:Brought Lambda beams to Nuclear Physics.

2: Twice the world sample in 750Mev – 2.5 GeV range (p)

3: Data points Error bars

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Special Thanks!

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Dr. John PriceCLAS collaborationJefferson LabNIGMS-RISE ProgramNIHColleagues at CSUDH

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Thank You

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FUTURE

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Cross Section Requires Clean up background

for exact # of events Find effective path

lengthPAC proposal • Dedicated experiment

for Λ beam

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Works Cited

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Scattering Cross-section Graph http://pdg.lbl.gov/2015/hadronic-xsections/rpp2014-

lambdap_sigmap_gp_gd_gg_plots.pdfPicture of CLAS Detector http://slideplayer.com/slide/1371778/ Picture of Real Detector https://www.google.com/search?q=CLAS+detector&espv=2&bi

w=1280&bih=705&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjepZXerMbLAhVL9GMKHaolA4oQ_AUIBygC#imgrc=jx78kxI3wJ-gJM%3A

PROTON https://en.wikipedia.org/wiki/Proton#/media/

File:Quark_structure_proton.svg Neutron https://en.wikipedia.org/wiki/Neutron#/media/

File:Quark_structure_neutron.svg

Works cited Cont.

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(Funnel pic) https://41perspectives.files.wordpress.com/2013/07/funnel-diagram-powerpoint2.jpg

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Probability of Scattering in G12

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Given our parameters how often should Λp→ Λp happen?

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Acceptance Rate

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CLAS has a 60% acceptance for positively-charged particles

50% acceptance for negatively-charged particles

Accounting for detected particles [K+π - p p] (0.6 *0.5 * 0.6 * 0.6) = 0.108 = 10.8%.Half of K+ Decay before hitting detector0.108 * 0.5 = 0.054 = 5.4 %

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