D. Goldstein

MICROCYSTIC ADNEXAL CARCINOMA, A DISTINCT CLINICOPATHOLOGIC ENTITY

Microcystic adnexal carcinoma is an unusual locally aggressive neoplasm that is important to recognize since it may be confused with benign adnexal neoplasms, particularly desmoplastic trichoepithelioma, trichoadenoma, and syringoma. Six cases are described all of which displayed benign histological features on initial biopsy. Most often these neoplasms presented as solitary flesh‐colored indurated plaques on the upper lip. All patients were white, five were women, and the average age was 44‐years‐old. Islands of basaloid keratinocytes, some of which contained horn cysts and abortive follicles, were embedded in a desmoplastic stroma. In other foci, ducts and gland‐like structures lined by a two‐cell layer predominated. In deep components individual and thin strands of cells dissected collagen bundles and skeletal muscle and invaded perineural spaces. Despite this, cytologic atypia and mitotic figures were rare. The cell of origin is considered to be a pluripotential adnexal keratinocyte which is capable of both follicular and sweat gland differentiation.

Observations of the Askaryan Effect in Ice

We report on observations of coherent, impulsive radio Cherenkov radiation from electromagnetic showers in solid ice. This is the first observation of the Askaryan effect in ice. As part of the complete validation process for the ANITA experiment, we performed an experiment at the Stanford Linear Accelerator Center in June 2006 using a 7.5 metric ton ice target. We measure for the first time the large-scale angular dependence of the radiation pattern, a major factor in determining the solid-angle acceptance of ultrahigh-energy neutrino detectors.

The Antarctic Impulsive Transient Antenna ultra-high energy neutrino detector: Design, performance, and sensitivity for the 2006–2007 balloon flight

Abstract We present a comprehensive report on the experimental details of the Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload, including the design philosophy and realization, physics simulations, performance of the instrument during its first Antarctic flight completed in January of 2007, and expectations for the limiting neutrino detection sensitivity.

New Limits on the Ultrahigh Energy Cosmic Neutrino Flux from the ANITA Experiment

We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of E(nu) approximately 3 x 10(18) eV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultrahigh energy extensive air showers.

Observation of ultrahigh-energy cosmic rays with the ANITA balloon-borne radio interferometer

We report the observation of 16 cosmic ray events with a mean energy of 1.5 × 10¹⁹ eV via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen events are seen to have a phase inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. Based on a likelihood analysis, we estimate angular pointing precision of order 2° for the event arrival directions.

In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for ultra-high energy (UHE) neutrino astronomy

Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an understanding of the radiofrequency (RF) response of cold polar ice. We herein report on a series of radioglaciological measurements performed approximately 10 km north of Taylor Dome Station, Antarctica from Dec. 6, 2006 - Dec. 16, 2006. Using RF signals broadcast from: a) an englacial discone, submerged to a depth of 100 meters and broadcasting to a surface dual polarization horn receiver, and b) a dual-polarization horn antenna on the surface transmitting signals which reflect off the underlying bed and back up to the surface receiver, we have made time-domain estimates of both the real (index-of-refraction) and imaginary (attenuation length) components of the complex ice dielectric constant. We have also measured the uniformity of ice response along two orthogonal axes in the horizontal plane. We observe a wavespeed asymmetry of order 0.1%, projected onto the vertical propagation axis, consistent with some previous measurements, but somewhat lower than others.

Initial results from the ANITA 2006-2007 Balloon Flight

We report initial results of the Antarctic Impulsive Transient Antenna (ANITA) 2006-2007 Long Duration Balloon flight, which searched for evidence of the flux of cosmogenic neutrinos. ANITA flew for 35 days looking for radio impulses that might be due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. In our initial high-threshold robust analysis, no neutrino candidates are seen, with no physics background. In a non-signal horizontal-polarization channel, we do detect 6 events consistent with radio impulses from extensive air showers, which helps to validate the effectiveness of our method. Upper limits derived from our analysis now begin to eliminate the highest cosmogenic neutrino models.

Upward-Pointing Cosmic-Ray-like Events Observed with ANITA

These proceedings address a recent publication by the ANITA collaboration of four upward- pointing cosmic-ray-like events observed in the first flight of ANITA. Three of these events were consistent with stratospheric cosmic-ray air showers where the axis of propagation does not inter- sect the surface of the Earth. The fourth event was consistent with a primary particle that emerges from the surface of the ice suggesting a possible {\tau}-lepton decay as the origin of this event. These proceedings follow-up on the modeling and testing of the hypothesis that this event was of {\tau} neutrino origin.

Introduction to the SalSA, a saltdome shower array as a GZK neutrino observatory

The observed spectrum of ultra-high energy cosmic rays virtually guarantees the presence of ultra-high energy neutrinos due to their interaction with the cosmic microwave background. Every one of these neutrinos will point back to its source and, unlike cosmic rays, will arrive at the Earth unattenuated, from sources perhaps as distant as z=20. The neutrino telescopes currently under construction, should discover a handful of these events, probably too few for detailed study. In this talk I will describe how an array of VHF and UHF antennas embedded in a large salt dome, SalSA (Saltdome Shower Array) promises to yield a teraton detector (> 500 km3-sr) for contained neutrino events with energies above 1017 eV. Our simulations show that such a detector may observe several hundreds of these neutrinos over its lifetime. Our simulations also show how such interactions will provide high energy physicists with an energy frontier for weak interactions an order-of-magnitude larger than that of the LHC. The flavor ID capalities of SALSA, combined with the extreme L/E of these neutrinos, will provide a window on neutrino oscillations and decay times eight orders of magnitude higher than laboratory experiments. In addition to the latest simulation results, we describe progress on detectors and site selection.

PRELIMINARY RESULT FROM ANITA EXPERIMENT

The ANITA (ANtarctic Impulsive Transient Antenna) experiment is a balloon-borne neutrino telescope which consists of an array of 32 broad-band horn antennas. It successfully completed a 35 day flight over Antarctica during the 2006-2007 austral summer. The primary goal of ANITA is to search for astrophysical neutrinos with energies E > 1019eV by detecting radio Cherenkov signals from neutrino induced showers in the Antarctic ice. We present preliminary results from ongoing analyses of ANITA data.