9 research outputs found
Resolving Boosted Jets with XCone
We show how the recently proposed XCone jet algorithm smoothly interpolates
between resolved and boosted kinematics. When using standard jet algorithms to
reconstruct the decays of hadronic resonances like top quarks and Higgs bosons,
one typically needs separate analysis strategies to handle the resolved regime
of well-separated jets and the boosted regime of fat jets with substructure.
XCone, by contrast, is an exclusive cone jet algorithm that always returns a
fixed number of jets, so jet regions remain resolved even when (sub)jets are
overlapping in the boosted regime. In this paper, we perform three LHC case
studies---dijet resonances, Higgs decays to bottom quarks, and all-hadronic top
pairs---that demonstrate the physics applications of XCone over a wide
kinematic range.Comment: 36 pages, 25 figures, 1 table; v2: references added; v3: discussion
added and new appendix B to match JHEP versio
XCone: N-jettiness as an exclusive cone jet algorithm
We introduce a new jet algorithm called XCone, for eXclusive Cone, which is based on minimizing the event shape N -jettiness. Because N -jettiness partitions every event into N jet regions and a beam region, XCone is an exclusive jet algorithm that always returns a fixed number of jets. We use a new “conical geometric” measure for which well-separated jets are bounded by circles of radius R in the rapidity-azimuth plane, while overlapping jet regions automatically form nearest-neighbor “clover jets”. This avoids the split/merge criteria needed in inclusive cone algorithms. A key feature of XCone is that it smoothly transitions between the resolved regime where the N signal jets of interest are well separated and the boosted regime where they overlap. The returned value of N -jettiness also provides a quality criterion of how N -jet-like the event looks. We also discuss the N -jettiness factorization theorems that occur for various jet measures, which can be used to compute the associated exclusive N -jet cross sections. In a companion paper [1], the physics potential of XCone is demonstrated using the examples of dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs.United States. Department of Energy (Offices of Nuclear and Particle Physics Contracts DE-SC00012567 and DE-SC0011090)Simons Foundation (Investigator grant 327942)United States. Department of Energy (Early Career research program DE-SC0006389)Alfred P. Sloan Foundation (Sloan Research Fellowship)Massachusetts Institute of Technology. Undergraduate Research Opportunities Program (Paul E. Gray Endowed Fund
Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100)
MAGIS-100 is a next-generation quantum sensor under construction at Fermilab
that aims to explore fundamental physics with atom interferometry over a
100-meter baseline. This novel detector will search for ultralight dark matter,
test quantum mechanics in new regimes, and serve as a technology pathfinder for
future gravitational wave detectors in a previously unexplored frequency band.
It combines techniques demonstrated in state-of-the-art 10-meter-scale atom
interferometers with the latest technological advances of the world's best
atomic clocks. MAGIS-100 will provide a development platform for a future
kilometer-scale detector that would be sufficiently sensitive to detect
gravitational waves from known sources. Here we present the science case for
the MAGIS concept, review the operating principles of the detector, describe
the instrument design, and study the detector systematics.Comment: 65 pages, 18 figure
Exclusive cone jet algorithms for high energy particle colliders
Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2015.Cataloged from PDF version of thesis.Includes bibliographical references (pages 59-62).In this thesis, I develop an exclusive cone jet algorithm based on the principles of jet substructure and demonstrate its use for physics analyses at the Large Hadron Collider. Based on the event shape N-jettiness, this algorithm, called "XCone," partitions the event into a fixed number of conical jets of size RO in the rapidity-azimuth plane. This algorithm is designed to locate substructure independent of momentum, allowing accurate resolution of jets at both low and high energy scales. I present three potential analyses using XCone to search for heavy resonances, Higgs bosons, and top quarks at various momenta and show that it reconstructs these particles with efficiencies between 60% and 80% without any additional substructure techniques, and maintains this efficiency over a wide kinematic range. This algorithm provides many key advantages over traditional jet algorithms that make it appealing for use at the LHC and other high energy particle colliders.by Thomas Frederick Wilkason, Jr.S.B
Atom Interferometry with Floquet Atom Optics
Floquet engineering offers a compelling approach for designing the time
evolution of periodically driven systems. We implement a periodic atom-light
coupling to realize Floquet atom optics on the strontium transition. These atom optics reach pulse efficiencies above
over a wide range of frequency offsets between light and atomic
resonance, even under strong driving where this detuning is on the order of the
Rabi frequency. Moreover, we use Floquet atom optics to compensate for
differential Doppler shifts in large momentum transfer atom interferometers and
achieve state-of-the-art momentum separation in excess of . This
technique can be applied to any two-level system at arbitrary coupling
strength, with broad application in coherent quantum control.Comment: 6 pages, 3 figures, plus supplemental materia