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LHC

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Full-Text Articles in Physics

Supersymmetric Discovery Potential And Benchmarks For Early Runs At √S=7  Tev At The Lhc, Baris Altunkaynak, Michael Holmes, Pran Nath, Brent D. Nelson, Gregory Peim May 2012

Supersymmetric Discovery Potential And Benchmarks For Early Runs At √S=7  Tev At The Lhc, Baris Altunkaynak, Michael Holmes, Pran Nath, Brent D. Nelson, Gregory Peim

Brent Nelson

We carry out an analysis of the potential of the Large Hadron Collider (LHC) to discover supersymmetry in runs at √s=7  TeV with an accumulated luminosity of (0.1–2)  fb⁻1 of data. The analysis is done with both minimal supergravity and supergravity models with nonuniversal soft breaking. Benchmarks for early discovery with (0.1–2)  fb⁻1 of data are given. We provide an update of b-tagging efficiencies in PGS 4 appropriate for LHC analyses. A large number of signature channels are analyzed, and it is shown that each of the models exhibited are discoverable at the 5σ level or more above the standard …


Predictive Signatures Of Supersymmetry: Measuring The Dark Matter Mass And Gluino Mass With Early Lhc Data, Daniel Feldman, Katherine Freese, Pran Nath, Brent D. Nelson, Gregory Peim May 2012

Predictive Signatures Of Supersymmetry: Measuring The Dark Matter Mass And Gluino Mass With Early Lhc Data, Daniel Feldman, Katherine Freese, Pran Nath, Brent D. Nelson, Gregory Peim

Brent Nelson

We present a focused study of a predictive unified model whose measurable consequences are immediately relevant to early discovery prospects of supersymmetry at the LHC. ATLAS and CMS have released their analysis with 35  pb-1 of data and the model class we discuss is consistent with this data. It is shown that with an increase in luminosity, the LSP dark matter mass and the gluino mass can be inferred from simple observables such as kinematic edges in leptonic channels and peak values in effective mass distributions. Specifically, we consider cases in which the neutralino is of low mass and where …


Supersymmetric Discovery Potential And Benchmarks For Early Runs At √S=7  Tev At The Lhc, Baris Altunkaynak, Michael Holmes, Pran Nath, Brent D. Nelson, Gregory Peim Apr 2012

Supersymmetric Discovery Potential And Benchmarks For Early Runs At √S=7  Tev At The Lhc, Baris Altunkaynak, Michael Holmes, Pran Nath, Brent D. Nelson, Gregory Peim

Pran Nath

We carry out an analysis of the potential of the Large Hadron Collider (LHC) to discover supersymmetry in runs at √s=7  TeV with an accumulated luminosity of (0.1–2)  fb⁻1 of data. The analysis is done with both minimal supergravity and supergravity models with nonuniversal soft breaking. Benchmarks for early discovery with (0.1–2)  fb⁻1 of data are given. We provide an update of b-tagging efficiencies in PGS 4 appropriate for LHC analyses. A large number of signature channels are analyzed, and it is shown that each of the models exhibited are discoverable at the 5σ level or more above the standard …


Gluino Nlsp, Dark Matter Via Gluino Coannihilation, And Lhc Signatures, Daniel Feldman, Zuowei Liu, Pran Nath Apr 2012

Gluino Nlsp, Dark Matter Via Gluino Coannihilation, And Lhc Signatures, Daniel Feldman, Zuowei Liu, Pran Nath

Pran Nath

The possibility that the gluino is the next to the lightest supersymmetric particle (NLSP) is discussed and it is shown that this situation arises in nonuniversal supergravity models within a significant part of the parameter space compatible with all known experimental bounds. It is then shown that the gluino NLSP (GNLSP) models lead to a compressed sfermion spectrum with the sleptons often heavier than the squarks at least for the first two generations. The relic density here is governed by gluino coannihilation which is responsible for a relatively small mass splitting between the gluino and the neutralino masses. Thus the …


Dijet Signals For Low Mass Strings At The Lhc, Luis A. Anchordoqui, Haim Goldberg, Dieter Lüst, Satoshi Nawata, Stephan Stieberger, Tomasz T. Taylor Feb 2011

Dijet Signals For Low Mass Strings At The Lhc, Luis A. Anchordoqui, Haim Goldberg, Dieter Lüst, Satoshi Nawata, Stephan Stieberger, Tomasz T. Taylor

Tomasz Taylor

We consider extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. Assuming that the fundamental string mass scale is in the TeV range and the theory is weakly coupled, we discuss possible signals of string physics at the Large Hadron Collider (LHC). In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets are completely independent of the details of compactification, and can be evaluated in …


Dijet Signals For Low Mass Strings At The Lhc, Luis A. Anchordoqui, Haim Goldberg, Dieter Lüst, Satoshi Nawata, Stephan Stieberger, Tomasz T. Taylor Feb 2011

Dijet Signals For Low Mass Strings At The Lhc, Luis A. Anchordoqui, Haim Goldberg, Dieter Lüst, Satoshi Nawata, Stephan Stieberger, Tomasz T. Taylor

Haim Goldberg

We consider extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. Assuming that the fundamental string mass scale is in the TeV range and the theory is weakly coupled, we discuss possible signals of string physics at the Large Hadron Collider (LHC). In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets are completely independent of the details of compactification, and can be evaluated in …


Dark Matter As A Guide Toward A Light Gluino At The Lhc, Daniel Feldman, Gordon Kane, Ran Lu, Brent T. Nelson Jan 2011

Dark Matter As A Guide Toward A Light Gluino At The Lhc, Daniel Feldman, Gordon Kane, Ran Lu, Brent T. Nelson

Brent Nelson

Motivated by specific connections to dark matter signatures, we study the prospects of observing the presence of a relatively light gluino whose mass is in the range ~ (500 − 900) GeV with a wino-like lightest supersymmetric particle with mass in the range of ~ (170 − 210) GeV. The light gaugino spectra studied here is generally different from other models, and in particular those with a wino dominated LSP, in that here the gluinos can be significantly lighter. The positron excess reported by the PAMELA satellite data is accounted for by annihilations of the wino LSP and their relic …


Black Hole Chromosphere At The Cern Lhc, Luis Anchordoqui, Haim Goldberg Jan 2011

Black Hole Chromosphere At The Cern Lhc, Luis Anchordoqui, Haim Goldberg

Haim Goldberg

If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the LHC. In this work we study the main properties of the light descendants of these black holes. We show that the emitted partons are closely spaced outside the horizon, and hence they do not fragment into hadrons in vacuum but more likely into a kind of quark-gluon plasma. Consequently, the thermal emission occurs far from the horizon, at a temperature characteristic of the QCD scale. We analyze the energy spectrum of the particles emerging from the "chromosphere", and find that the hard …


Decoding The Mechanism For The Origin Of Dark Matter In The Early Universe Using Lhc Data, Daniel Feldman, Zuowei Liu, Pran Nath Jan 2011

Decoding The Mechanism For The Origin Of Dark Matter In The Early Universe Using Lhc Data, Daniel Feldman, Zuowei Liu, Pran Nath

Pran Nath

It is shown that LHC data can allow one to decode the mechanism by which dark matter is generated in the early universe in supersymmetric theories. We focus on two of the major mechanisms for such generation of dark matter which are known to be the Stau Coannihilation (Stau-Co) where the neutralino is typically Bino like and annihilation on the Hyperbolic Branch (HB) where the neutralino has a significant Higgsino component. An investigation of how one may discriminate between the Stau-Co region and the HB region using LHC data is given for the mSUGRA model. The analysis utilizes several signatures …


Connecting The Direct Detection Of Dark Matter With Observation Of Sparticles At The Lhc, Daniel Feldman, Zuowei Liu, Pran Nath Jan 2011

Connecting The Direct Detection Of Dark Matter With Observation Of Sparticles At The Lhc, Daniel Feldman, Zuowei Liu, Pran Nath

Pran Nath

An analysis is given connecting event rates for the direct detection of neutralino dark matter with the possible signatures of supersymmetry at the LHC. It is shown that if an effect is seen in the direct detection experiments at a level of O(10⁻⁴⁴) cm² for the neutralino-proton cross section, then within the mSUGRA model the next heavier particle above the neutralino is either a stau, a chargino, or a CP odd/CP even (A/H) Higgs boson. Further, the collider analysis shows that models with a neutralino-proton cross section at the level of (1 − 5) × 10⁻⁴⁴ cm² could be probed …