Physics with a High Intensity Proton Source at Fermilab: Project X Golden Book

Within the next ten years the Standard Model will likely have to be modified to encompass a wide range of newly discovered phenomena, new elementary particles, new symmetries, and new dynamics. These phenomena will be revealed through experiment with high energy particle accelerators, mainly the LHC. This will represent a revolution in our understanding of nature, and will either bring us closer to an understanding of all phenomena, through existing ideas such as supersymmetry to superstrings, or will cause us to scramble to find new ideas and a new sense of direction. We are thus entering a dramatic and important time in the quest to understand the fundamental laws of nature and their role in shaping the universe. The energy scales now probed by the Tevatron, of order hundreds of GeV, will soon be subsumed by the LHC and extended up to a few TeV. We expect the unknown structure of the mysterious symmetry breaking of the Standard Model to be revealed. We will then learn the answer to a question that has a fundamental bearing upon our own existence: 'What is the origin of mass?' All modern theories of 'electroweak symmetry breaking' involve many new particles, mainly to provide a 'naturalness' rationale for the weak scale. Supersymmetry (SUSY) represents extra (fermionic) dimensions of space, leading to a doubling of the number of known elementary particles and ushering in many additional new particles and phenomena associated with the various symmetry breaking sectors. The possibility of additional bosonic dimensions of space would likewise usher in an even greater multitude of new states and new phenomena. Alternatively, any new spectroscopy may indicate new principles we have not yet anticipated, and we may see new strong forces and/or a dynamical origin of mass. The wealth of new particles, parameters, CP-phases, and other phenomena carries important implications for precision quark flavor physics experiments that are uniquely sensitive probes of new phenomena. We have already begun to see the enlargement of the Standard Model in the leptonic sector. Neutrino masses and mixing angles, which in the early 1990's were unknown, must now be incorporated into our full description of nature. In a minimal scenario of Majorana masses and mixings amongst the three known left-handed neutrinos, we see a strong hint of a new and very large mass scale, possibly associated with grand unification or the scale of quantum gravity, the Planck mass. We are not yet sure what the proper description of neutrino masses and mixing angles will be. Experiments may reveal additional unexpected particles coupled to the neutrino sector. New phenomena, such as leptonic CP-violation, will be major focal points of our expanding understanding of the lepton sector. There is much to be done with experiment to attack the issues that neutrinos now present. Already, developments in neutrino physics and the possibility of a novel source of CP-violation in the lepton sector have spawned hopes that the cosmic matter-antimatter asymmetry may be explained through leptogenesis. Neutrino physics, together with the search for new energy frontier physics, offers the possibility of experimental handles on the questions of dark matter and dark energy. Without the discovery of new particles in accelerator experiments, the telescope-based cosmological observations of the early universe would remain unexplained puzzles. The process of understanding the laws of physics in greater detail through accelerator-based high energy physics will potentially have incisive impact on our understanding of dark matter and dark energy. Precision flavor physics in both the quark and the lepton sectors offers a window on the sensitive entanglement of beyond-the-Standard-Model physics with rare processes, through quantum loop effects involving known or new states. Flavor physics offers sensitive indirect probes and may be the first place to reveal additional key components of the post-Standard Model physics. The main arenas for quark flavor physics include strange, charm and beauty, hence kaons, D-mesons, B-mesons and heavy baryons. A remarkable historical paradigm for the importance of flavor physics is the well known suppression of flavor-changing neutral currents. The analysis of the K{sub L}-K{sub S} mass difference by Gaillard and Lee, 35 years ago in the Fermilab Theory Group, led to the confirmation of the GIM mechanism and predicted the mass of the charm quark, m{sub c} {approx} 1.5 GeV, definitively and prior to its discovery. This, today, implies an astonishing constraint on SUSY models, e.g., that the down and strange squarks are mass degenerate to 1:10{sup 5}. This, in turn, has spawned a new working hypothesis called 'Minimal Flavor Violation' (MFV). But is MFV really a true principle operating in nature and, if so, where does it come from? Such questions can only be addressed in precision flavor physics experiments

Joint Observation of the Galactic Center with MAGIC and CTA-LST-1

MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes (IACTs), designed to detect very-high-energy gamma rays, and is operating in stereoscopic mode since 2009 at the Observatorio del Roque de Los Muchachos in La Palma, Spain. In 2018, the prototype IACT of the Large-Sized Telescope (LST-1) for the Cherenkov Telescope Array, a next-generation ground-based gamma-ray observatory, was inaugurated at the same site, at a distance of approximately 100 meters from the MAGIC telescopes. Using joint observations between MAGIC and LST-1, we developed a dedicated analysis pipeline and established the threefold telescope system via software, achieving the highest sensitivity in the northern hemisphere. Based on this enhanced performance, MAGIC and LST-1 have been jointly and regularly observing the Galactic Center, a region of paramount importance and complexity for IACTs. In particular, the gamma-ray emission from the dynamical center of the Milky Way is under debate. Although previous measurements suggested that a supermassive black hole Sagittarius A* plays a primary role, its radiation mechanism remains unclear, mainly due to limited angular resolution and sensitivity. The enhanced sensitivity in our novel approach is thus expected to provide new insights into the question. We here present the current status of the data analysis for the Galactic Center joint MAGIC and LST-1 observations

MAGIC and H.E.S.S. detect VHE gamma rays from the blazar OT081 for the first time: a deep multiwavelength study

https://pos.sissa.it/395/815/pdfPublished versio

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

Anelastic phenomena and Cr2N precipitation in a high nitrogen austenitic steel

Internal friction (IF) and dynamic modulus measurements on a high nitrogen (0.8 wt%) austenitic steel in the temperature range from room temperature to 800 °C have been carried out by using a vibrating reed technique with electrostatic excitation and frequency modulation detection of flexural vibrations in the frequency range of kHz. The IF spectrum of the as-prepared material shows a broad peak superimposed to an exponentially increasing background. The discontinuous precipitation of Cr2N phase changes the characteristics of the peak. The results have been discussed by considering interstitial-substitutional (i-s) interactions

Anelastic Phenomena and Cr<sub>2</sub>N Precipitation in a High Nitrogen Austenitic Steel

Internal friction (IF) and dynamic modulus measurements on a high nitrogen (0.8 wt%) austenitic steel in the temperature range from room temperature to 800 °C have been carried out by using a vibrating reed technique with electrostatic excitation and frequency modulation detection of flexural vibrations in the frequency range of kHz. The IF spectrum of the as-prepared material shows a broad peak superimposed to an exponentially increasing background. The discontinuous precipitation of Cr2N phase changes the characteristics of the peak. The results have been discussed by considering interstitial-substitutional (i-s) interactions.</jats:p

Discontinuous Precipitation in a High-Nitrogen Austenitic Steel

The discontinuous precipitation of a high-nitrogen (0.8 wt%) austenitic steel has been investigated after successive steps of heat treatment at two different temperatures (800 and 850 °C). After each step of heating the material has been examined by X-ray diffraction (XRD), optical microscopy (OM), transmission electron microscopy (TEM), Auger electron spectroscopy (AES) and microhardness tests. The precipitation of Cr2N induces the formation of a secondary austenitic phase, leads to the redistribution of N between transformed and untransformed zones and to local variations of mechanical properties.</jats:p