$$\Lambda $$CDM: Much More Than We Expected,but Now Less Than What We Want

The \(\Lambda \)CDM cosmological model is remarkable: with just six parameters it describes the evolution of the Universe from a very early time when all structures were quantum fluctuations on subatomic scales to the present, and it is consistent with a wealth of high-precision data, both laboratory measurements and astronomical observations. However, the foundation of \(\Lambda \)CDM involves physics beyond the standard model of particle physics: particle dark matter, dark energy and cosmic inflation. Until this ‘new physics’ is clarified, \(\Lambda \)CDM is at best incomplete and at worst a phenomenological construct that accommodates the data. I discuss the path forward, which involves both discovery and disruption, some grand challenges and finally the limits of scientific cosmology.     

Particle physics implications for CoGeNT, DAMA, and Fermi

Recent results from the CoGeNT Collaboration (as well as the annual modulation reported by DAMA/LIBRA) point toward dark matter with a light (5-10 GeV) mass and a relatively large elastic scattering cross section with nucleons (σ∼¹⁰−40 cm²). In order to possess this cross section, the dark matter must communicate with the Standard Model through mediating particles with small masses and/or large couplings. In this Letter, we explore with a model-independent approach the particle physics scenarios that could potentially accommodate these signals. We also discuss how such models could produce the gamma rays from the Galactic Center observed in the data of the Fermi Gamma-Ray Space Telescope. We find multiple particle physics scenarios in which each of these signals can be accounted for, and in which the dark matter can be produced thermally in the early Universe with an abundance equal to the measured cosmological density.     

粒子物理和宇宙学中的两片乌云——谈暗物质和暗能量

宇宙暗物质和暗能量是21世纪粒子物理和宇宙学研究中的两个重大的科学问题.文章首先简述了宇宙学研究的历史和现状以及对粒子物理学提出的新的挑战,接着较详细地介绍了暗物质、暗能量和反物质相关的科学问题以及在国际上这个研究领域近年来所取得的进展,最后展望了中国在暗物质和暗能量实验探测研究方面的前景.     

AD: low-energy antiproton production at CERN

Well into its 10th year of running for physics, the Antiproton Decelerator (AD) supplies antiprotons to 4 different physics collaborations: ATRAP, ALPHA, ASACUSA and ACE. Antiprotons are injected at 3.5 GeV/c, then cooled and decelerated before being extracted at 100, 300 or 500 MeV/c in single or multi-batch mode. Here we will discuss the challenges of keeping reliability and performance at adequate levels, prospects of future physics scheduling and also possible additional experiments and machine improvements.     

Observational constraints on the time-dependence of dark energy

One of the most important questions nowadays in physics concerns the nature of the so-called dark energy. It is also a consensus among cosmologists that such a question will not be answered on the basis only of observational data. However, it is possible to diminish the range of possibilities for this dark component by comparing different dark energy scenarios and finding which models can be ruled out by current observations. In this paper, by assuming three distinct parametrizations for the low-redshift evolution of the dark energy equation of state (EOS), we consider the possibility of discriminating between evolving dark energy and ΛCDM models from a joint analysis involving the most recent radio sources gravitational lensing sample, namely, the Cosmic all Sky Survey (CLASS) statistical data and the recently published gold SNe Ia sample. It is shown that this particular combination of observational data restricts considerably the dark energy parameter space, which enables possible distinctions between time-dependent and constant EOSs.     

Darkon dark matter, unparticle effects and collider physics

In this talk I report recent results on the simplest dark matter model, the Darkon model, and supersymmetric unparticle effects on dark matter, and some implications for coUider physics. I first discuss dark matter properties and collider signatures in the Darkon model, and then I discuss some implications for dark matter if a scalar unparticle is introduced to the MSSM.     

Darkon dark matter,unparticle effects and collider physics

In this talk I report recent results on the simplest dark matter model, the Darkon model, and supersymmetric unparticle effects on dark matter, and some implications for collider physics. I first discuss dark matter properties and collider signatures in the Darkon model, and then I discuss some implications for dark matter if a scalar unparticle is introduced to the MSSM.     

On the continuing relevance of Mandelbrot’s non-ergodic fractional renewal models of 1963 to 1967

The problem of “1∕f” noise has been with us for about a century. Because it is so often framed in Fourier spectral language, the most famous solutions have tended to be the stationary long range dependent (LRD) models such as Mandelbrot’s fractional Gaussian noise. In view of the increasing importance to physics of non-ergodic fractional renewal models, and their links to the CTRW, I present preliminary results of my research into the history of Mandelbrot’s very little known work in that area from 1963 to 1967. I speculate about how the lack of awareness of this work in the physics and statistics communities may have affected the development of complexity science, and I discuss the differences between the Hurst effect, “1∕f” noise and LRD, concepts which are often treated as equivalent.     

Doubly-charged scalar bosons from the doublet

We consider the extended Higgs models, in which one of the isospin doublet scalar fields carries the hypercharge Y=3/2. Such a doublet field Φ3/2 is composed of a doubly charged scalar boson as well as a singly charged one. We first discuss a simple model with Φ3/2 (Model I), and study its collider phenomenology at the LHC. We then consider a new model for radiatively generating neutrino masses with a dark matter candidate (Model II), in which Φ3/2 and an extra Y=1/2 doublet as well as vector-like singlet fermions carry the odd quantum number for an unbroken discrete Z₂ symmetry. We also discuss the neutrino mass model (Model III), in which the exact Z₂ parity in Model II is softly broken. It is found that the doubly charged scalar bosons in these models show different phenomenological aspects from those which appear in models with a Y=2 isospin singlet field or a Y=1 triplet one. They could be clearly distinguished at the LHC.     

Radiative see-saw formula in nonsupersymmetric SO(10) with dark matter

In SO(10), the type-I and type-II see-saw scales ???10¹² GeV are far away from being probed by direct experimental tests. In the absence of supersymmetry, we show how experimentally verifiable radiative see-saw formula of Ma type is realized in non-SUSY SO(10) while fulfilling the twin objectives: precision gauge coupling unification and dark matter. This model is expected to have a dramatic impact on neutrino physics, dark matter and all fermion masses and mixings.     

SEWDarkM

A number of observed phenomena in high energy physics and cosmology lack their resolution within the Standard Model of particle physics. These puzzles include neutrino oscillations, baryon asymmetry of the Universe, existence of Dark Matter and inflation. We discuss the suggestion, based on the νMSM (an extension of the Standard Model by three light singlet fermions) that all these problems can be solved by new physics which exists only below the electroweak scale. We describe the formalism which allows to compute from first principles of quantum field theory and statistical physics the abundance of dark matter in this theory. Predictions of the νMSM are compared with results of different cosmological and astrophysical observations.     

Physics Textbooks Don’t Always Tell the Truth

Anyone who studies the history of physics quickly realizes that the history presented in physics textbooks is often inaccurate. I will discuss three episodes from the history of modern physics: (1) Robert Millikan’s experiments on the photoelectric effect, (2) the Michelson-Morley experiment, and (3) the Ellis-Wooster experiment on the energy spectrum in β decay. Everyone knows that Millikan’s work established the photon theory of light and that the Michelson-Morley experiment was crucial in the genesis of Albert Einstein’s special theory of relativity. The problem is that what everyone knows is wrong. Neither experiment played the role assigned to it by physics textbooks. The Ellis-Wooster experiment, on the other hand, is rarely discussed in physics texts, but it should be. It led to Wolfgang Pauli’s suggestion of the neutrino. I will present a more accurate history of these three experiments than those given in physics texts.     

The Merli–Missiroli–Pozzi Two-Slit Electron-Interference Experiment

In 2002 readers of Physics World voted Young??s double-slit experiment with single electrons as ??the most beautiful experiment in physics?? of all time. Pier Giorgio Merli, Gian Franco Missiroli, and Giulio Pozzi carried out this experiment in a collaboration between the Italian Research Council and the University of Bologna almost three decades earlier. I examine their experiment, place it in historical context, and discuss its philosophical implications.     

The Mathematical Universe

I explore physics implications of the External Reality Hypothesis (ERH) that there exists an external physical reality completely independent of us humans. I argue that with a sufficiently broad definition of mathematics, it implies the Mathematical Universe Hypothesis (MUH) that our physical world is an abstract mathematical structure. I discuss various implications of the ERH and MUH, ranging from standard physics topics like symmetries, irreducible representations, units, free parameters, randomness and initial conditions to broader issues like consciousness, parallel universes and Gödel incompleteness. I hypothesize that only computable and decidable (in Gödel’s sense) structures exist, which alleviates the cosmological measure problem and may help explain why our physical laws appear so simple. I also comment on the intimate relation between mathematical structures, computations, simulations and physical systems.     

Dark DC conductivity and spectroscopy of clean and gas doped thin films of organic semiconductors

The dark DC conductivity of thin films of phthalocyanine (I), meso-tetra(p-methylphenyl)porphin (II), meso-tetraphenylporphin (III), hemiporphyrazine (IV), dihydrodibenzo [b,i][1,4,8,11] tetra-azacyclotetradecine (V) and three derivatives of V have been studied in vacuo and in the presence of a wide range of gases. The only gases to produce marked increases in the conductivity were electron acceptors; however, IV was unaffected even by these. The interactions of I, II, III and V and its derivatives with $\text{NO}{}_2\text{N}{}_2\text{O}{}_4$ (NOX) were of particular interest and were studied by conductivity measurements, UV/VIS and IR transmission spectroscopy and IR reflectance spectroscopy. The material most sensitive to NOX and other electron acceptors was I; however, V has a favourable combination of sensitivity coupled with reversibility at room temperature. The Interactions of NOX with I, II and HI are complex, and there is spectroscopic evidence for the generation of NO₂ and the organic radical cations.     

Dynamical interactions of dark energy and dark matter:Yang-Mills condensate and QCD axions

We analyze a model of cold axion dark matter weakly coupled with a dark gluon condensate,reproducing dark energy.We first review how to recover the dark energy behavior using the functional renormalization group approach,and ground our study in the properties of the effective Lagrangian,to be determined non-perturbatively.Then,within the context of G_(SM)×SU(2)_D×U(1)_(P Q),we consider Yang-Mills condensate(YMC)interactions with QCD axions.We predict a transfer of dark energy density into dark matter density,that can be tested in the next generation of experiments dedicated to dark energy measurements.We obtain new bounds on the interactions between the Yang-Mills condensate and axion dark matter from Planck data:the new physics interaction scale related to the axion/gluon condensate mixing is constrained to be higher than the 10~6GeV energy scale.     

Photonic dark matter portal and quantum physics

We study a model of dark matter in which the hidden sector interacts with standard model particles via a hidden photonic portal.We investigate the effects of this new interaction on the hydrogen atom,including the Stark,Zeeman and hyperfine effects.Using the accuracy of the measurement of energy,we obtain an upper bound for the coupling constant of the model as f≤10~(-12).We also calculate the contribution from the hidden photonic portal to the anomalous magnetic moment of the muon as α_μ≤ 2.2 × 10~(-23)(for the dark particle mass scale 100MeV),which provides an important probe of physics beyond the standard model.