Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSearch for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing
153
0
0.0
(
0
)
Authors
CDF Collaboration
Ask ChatGPT about the research
No Arabic abstract
We present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via lightest neutralino to gamma gravitino in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of $570pm34 pb^{-1}$ of $pbar{p}$ collisions at $sqrt{s}=1.96$ TeV, we select $gamma$+jet+missing transverse energy candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. We find 2 events, consistent with the background estimate of 1.3$pm$0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits and place the world-best 95% C.L. lower limit on the neutralino mass of 101 GeV at lifetime = 5 ns.
rate research
Read More
We describe a novel way to measure the mass of heavy, long-lived neutral particles that decay to photons using collider experiments. We focus on a Light Neutralino and Gravitino model in a Gauge Mediated Supersymmetry Breaking scenario where the neutralino has a long-lifetime (O(ns)) as it is not excluded by current experiments. To illustrate our method and give sensitivity estimates we use recent CDF results and a production mechanism where sparticles are produced via $phi_{i} rightarrow widetilde{chi}^{1}_{0} widetilde{chi}^{1}_{0} rightarrow (gamma widetilde{G})(gamma widetilde{G})$ in which $phi_{i}$ indicates a neutral scalar boson, $widetilde{chi}^{1}_{0}$ is the lightest neutralino and $widetilde{G}$ is the gravitino, as a full set of background shapes and rates are available. Events can be observed in the exclusive photon plus Missing $E_{T}$ final state where one photon arrives at the detector with a delayed time of arrival. Surprisingly, a simple measurement of the slope of the delayed-time distribution with the full CDF dataset is largely insensitive to all but the $widetilde{chi}^{1}_{0}$ mass and allows for the possibility of determining its mass to approximately 25% of itself.
A search is performed for heavy long-lived charged particles using 3.0 fb$^{-1}$ of pp collisions collected at $sqrt{s}$= 7 and 8 TeV with the LHCb detector. The search is mainly based on the response of the ring imaging Cherenkovdetectors to distinguish the heavy, slow-moving particles from muons. No evidence is found for the production of such long-lived states. The results are expressed as limits on the Drell-Yan production of pairs of long-lived particles, with both particles in the LHCb pseudorapidity acceptance, $1.8 < eta < 4.9$. The mass-dependent cross-section upper limits are in the range 2-4 fb (at 95% CL) for masses between 124 and 309 GeV/c$^2$.
A search is presented for long-lived particles with a mass between 25 and 50 GeV$/c^2$ and a lifetime between 1 and 200 ps in a sample of proton-proton collisions at a centre-of-mass energy of $sqrt{s}=7$ TeV, corresponding to an integrated luminosity of 0.62 fb$^{-1}$, collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a Standard Model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime.
We present the result of direct leptoquark searches based on 110 pb-1 of integrated luminosity collected by the Collider Detector at Fermilab during the 1992-93 and 1994-95 Tevatron runs at sqrt{s}=1.8 TeV. We present upper limits on the production cross sections as a function of the leptoquark mass. Using the NLO calculation of the leptoquark-pair production cross sections we extract lower-mass limits for first, second and third generation leptoquarks. We also present the result of an indirect search for Pati-Salam leptoquarks via exclusive e-mu decay modes of B^{0}_{s} and B^{0}_{d}.
A search is presented for long-lived particles with a mass between 25 and 50 GeV/$c^2$ and a lifetime between 2 and 500 ps, using proton-proton collision data corresponding to an integrated luminosity of 2.0 fb$^{-1}$, collected by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The particles are assumed to be pair-produced in the decay of a 125 GeV/$c^2$ Standard-Model-like Higgs boson. The experimental signature is a single long-lived particle, identified by a displaced vertex with two associated jets. No excess above background is observed and limits are set on the production cross-section as a function of the mass and lifetime of the long-lived particle.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
