Biography:

In the past Francis Halzen has collaborated on articles with Kaoru Hagiwara and E.W.N. Glover. One of their most recent publications is Jets in pp collisions: Radiation zeroes and the electric charges of colored quarks. Which was published in journal Physics Letters B.

More information about Francis Halzen research including statistics on their citations can be found on their Copernicus Academic profile page.

Francis Halzen's Articles: (11)

Jets in pp collisions: Radiation zeroes and the electric charges of colored quarks

AbstractMeasurements involving more than one photon (e.g., γγ → hadrons, e+e- → qqγ) can determine the electric charge of colored quarks rather than the color-averaged value measured, for example, by the R-value in e+e- → hadrons. We draw attention to the fact that this measurement of the absolute quark charges can be performed in hadron collisions via the process qq → qqγ. The charge signature is dramatic due to the appearance of radiation zeroes whose position depends on the values of the electric charges. This can be exploited to perform such measurements with a detector lacking γ/π0 separation capability. Such experiments also study the interface of color and electromagnetic amplitudes and can further elucidate the QCD origin of jets.

J/ψ as a flavour tag for fourth-generation b′ quarks

AbstractThe decay b→ψX offers an excellent tag for hadroproduced b quarks. Similarly the decay b′→ψX is a particularly clear signature for a fourth-generation b′ quark if mb′mb and pT(ψ).

Counting neutrinos with monojets

AbstractIn proton-antiproton collisions, the Z to W cross-section ratio at large pT is appreciably different from the total Z to W ratio. We drive the relation (dσ/dpT)(W±) · BR(W→ev) ≅ (dσ/dpT)(Z) · BR(Z →vv) for sufficiently large pT, which is valid for three generations. As excess of “monojet” events would signal additional light neutrinos. This method is more sensitive to the variation of nv than the Z total width measurement or the method of total Z → e+e-/W → ev ratio.

IceHEP high energy physics at the South Pole

AbstractWith the solar and SN87 neutrino observations as proofs of concepts, the kilometer-scale neutrino experiment IceCube will scrutinize its data for new particle physics. In this paper, we review the prospects for the realization of such a program. We begin with a short overview of the detector response and discuss the reach of “beam” luminosity. After that we discuss the potential of IceCube to probe deviations of neutrino-nucleon cross-sections from the Standard Model predictions at center-of-mass energies well beyond those accessible in man-made accelerators. Then we review the prospects for extremely long-baseline analyses and discuss the sensitivity to measure tiny deviations of the flavor mixing angle, expected to be induced by quantum gravity effects. Finally, we discuss the potential to uncover annihilation of dark matter particles gravitationally trapped at the center of the Sun, as well as processes occurring in the early Universe at energies close to the Grand Unification scale.

High energy neutrino astronomy: first light

AbstractWe review: 1.The compelling case for doing neutrino astronomy,2.Why we anticipate that we need kilometer-scale observatories to do the science,3.The recent successful commissioning of the Lake Baikal and South Pole neutrino detectors.

Neutrinos from the annihilation or decay of superheavy relic dark matter particles

AbstractIn light of the mounting evidence that the highest energy cosmic rays are dominated by protons and not gamma-rays, we discuss the prospect that these cosmic rays are generated in the decay or annihilation of superheavy relic particles. We calculate the high energy neutrino spectrum which results and normalize our results to the ultra-high energy cosmic ray spectrum. We show that most scenerios are already constrained by present limits placed by the AMANDA experiment.

High-Energy Neutrino Astronomy

Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of 1020 and 1013 eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of the completed AMANDA detector and the reach of its extension, IceCube. Similar experiments are under construction in the Mediterranean.

Large natural Cherenkov detectors: Water and ice

AbstractIn this review we first address 2 questions: •• why do we need kilometer-scale muon and neutrino detectors?•• what do we learn from the operating Baikal and AMANDA detectors about the construction of kilometer-scale detectors?I will subsequently discuss the challenges for building the next-generation detectors. The main message is that these are different, in fact less ominous, than for commissioning the present, relatively small, detectors which must reconstruct events far outside their instrumented volume in order to achieve large effective telescope area.

Coincident GRB neutrino flux predictions: Implications for experimental UHE neutrino physics

AbstractIn the hadronic fireball phenomenology of Gamma Ray Bursts (GRBs), it is expected that the observed photons are accompanied by UHE neutrinos, which have not been observed yet. It is one of the challenges of experimental UHE neutrino astrophysics to look for a signal from GRBs. In this paper, the differences between a search for a diffuse signal and an examination of a source sample given by e.g. BATSE will be analyzed. Since redshift information is needed to determine the correct energy spectrum, long duration bursts with redshifts from different estimate methods will be used. We will start with an overview of the current understanding of GRB neutrino physics and will then use this knowledge to make predictions for a coincidence flux and a corresponding diffuse flux. It can be shown that shape and normalization of the spectrum is highly dependent on the set of bursts used and that individual bursts can determine the total spectrum.

Pionic photons and neutrinos from cosmic ray accelerators

AbstractIdentifying the accelerators that produce the Galactic and extragalactic cosmic rays has been a priority mission of several generations of high energy gamma ray and neutrino telescopes; success has been elusive so far. Detecting the gamma-ray and neutrino fluxes associated with cosmic rays reaches a new watershed with the completion of IceCube, the first neutrino detector with sensitivity to the anticipated fluxes, and the construction of CTA, a ground-based gamma ray detector that will map and study candidate sources with unprecedented precision. In this paper, we revisit the prospects for revealing the sources of the cosmic rays by a multiwavelength approach; after reviewing the methods, we discuss supernova remnants, gamma ray bursts, active galaxies and GZK neutrinos in some detail.

Neutrino astronomy: An update

AbstractDetecting neutrinos associated with the still enigmatic sources of cosmic rays has reached a new watershed with the completion of IceCube, the first detector with sensitivity to the anticipated fluxes. In this review, we will briefly revisit the rationale for constructing kilometer-scale neutrino detectors and summarize the status of the field.

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