Coronary Artery Disease: from Atherosclerosis to Cardiogenic Shock

__Abstract__ The aim of this thesis is twofold: 1. to investigate the prognostic value of intracoronary imaging and blood biomarkers in patients with coronary artery di

A CMOS spectrum analyzer frontend for cognitive radio achieving +25dBm IIP3 and −169 dBm/Hz DANL

A dual RF-receiver preceded by discrete-step attenuators is implemented in 65nm CMOS and operates from 0.3– 1.0 GHz. The noise of the receivers is reduced by cross-correlating the two receiver outputs in the digital baseband, allowing attenuation of the RF input signal to increase linearity. With this technique a displayed average noise level below -169 dBm/Hz is obtained with +25 dBm IIP3, giving a spurious-free dynamic range of 89 dB in 1 MHz resolution bandwidth

A flicker noise/IM3 cancellation technique for active mixer using negative impedance

This paper presents an approach to simultaneously cancel flicker noise and IM3 in Gilbert-type mixers, utilizing negative impedances. For proof of concept, two prototype double-balanced mixers in 0.16- m CMOS are fabricated. The first demonstration mixer chip was optimized for full IM3 cancellation and partial flicker noise cancellation; this chip achieves 9-dB flicker noise suppression, improvements of 10 dB for IIP3, 5 dB for conversion gain, and 1 dB for input P1 dB while the thermal noise increased by 0.1 dB. The negative impedance increases the power consumption for the mixer by 16% and increases the die area by 8% (46 28 m ). A second demonstration mixer chip aims at full flicker noise cancellation and partial IM3 cancellation, while operating on a low supply voltage ( 0.67 x Vdd; in this chip,the negative impedance increases the power consumption by 7.3% and increases the die area by 7% (50 20 m ). For one chip sample, measurements show 10-dB flicker noise suppression within 200% variation of the negative impedance bias current; for ten randomly selected chip samples, 11-dB flicker noise suppression is measured

Implications of Recent Measurements of Hadronic Charmless B Decays

Implications of recent CLEO measurements of hadronic charmless B decays are discussed. (i) Employing the Bauer-Stech-Wirbel (BSW) model for form factors as a benchmark, the $B\to\pi^+\pi^-$ data indicate that the form factor $F_0^{B\pi}(0)$ is smaller than that predicted by the BSW model, whereas the data of $B\to\omega\pi, K^*\eta$ imply that the form factors $A_0^{B\omega}(0), A_0^{BK^*}(0)$ are greater than the BSW model's values. (ii) The tree-dominated modes $B\to\pi^+\pi^-, \rho^0\pi^\pm, \omega\pi^\pm$ imply that the effective number of colors N_c(LL) for (V-A)(V-A) operators is preferred to be smaller, while the current limit on $B\to\phi K$ shows that N_c(LR)>3. The data of $B\to K\eta'$ and $K^*\eta$ clearly indicate that $N_c(LR)\gg N_c(LL)$. (iii) In order to understand the observed suppression of $\pi^+\pi^-$ and non-suppression of $K\pi$ modes, both being governed by the form factor $F_0^{B\pi}$, the unitarity angle $\gamma$ is preferred to be greater than $90^\circ$. By contrast, the new measurement of $B^\pm\to\rho^0\pi^\pm$ no longer strongly favors $\cos\gamma<0$. (iv) The observed pattern K^-\pi^+\sim \ov K^0\pi^-\sim {2\over 3}K^-\pi^0 is consistent with the theoretical expectation: The constructive interference between electroweak and QCD penguin diagrams in the $K^-\pi^0$ mode explains why {\cal B}(B^-\to K^-\pi^0)>{1\over 2}{\cal B}(\ov B^0\to K^-\pi^+). (v) The observation \nc(LL)<3<\nc(LR) and our preference for \nc(LL)\sim 2 and \nc(LR)\sim 6 are justified by a recent perturbative QCD calculation of hadronic rare B decays in the heavy quark limit.Comment: 21 pages; CLEO measurements of several charmless B decay modes are updated. Discussion of the unitarity angle gamma in the \rho\pi mode is revise

Spin Measurements in Cascade Decays at the LHC

We systematically study the possibility of determining the spin of new particles after their discovery at the LHC. We concentrate on angular correlations in cascade decays. Motivated by constraints of electroweak precision tests and the potential of providing a Cold Dark Matter candidate, we focus on scenarios of new physics in which some discrete symmetry guarantees the existence of stable neutral particles which escape the detector. More specifically, we compare supersymmetry with another generic scenario in which new physics particles have the same spin as their Standard Model partners. A survey of possibilities of observing spin correlations in a broad range of decay channels is carried out, with interesting ones identified. Rather than confining ourselves to one "collider friendly" benchmark point (such as SPS1a), we describe the parameter region in which any particular decay channel is effective. We conduct a more detailed study of chargino's spin determination in the decay channel $\tilde{q}\to q + \tilde{C}^\pm \to q + W^\pm + LSP$. A scan over the chargino and neutralino masses is performed. We find that as long as the spectrum is not too degenerate the prospects for spin determination in this channel are rather good.Comment: 36 pages, references added, 1 figure modifie

Mass Determination in SUSY-like Events with Missing Energy

We describe a kinematic method which is capable of determining the overall mass scale in SUSY-like events at a hadron collider with two missing (dark matter) particles. We focus on the kinematic topology in which a pair of identical particles is produced with each decaying to two leptons and an invisible particle (schematically, $pp\to YY+jets$ followed by each $Y$ decaying via $Y\to \ell X\to \ell\ell'N$ where $N$ is invisible). This topology arises in many SUSY processes such as squark and gluino production and decay, not to mention t\anti t di-lepton decays. In the example where the final state leptons are all muons, our errors on the masses of the particles $Y$, $X$ and $N$ in the decay chain range from 4 GeV for 2000 events after cuts to 13 GeV for 400 events after cuts. Errors for mass differences are much smaller. Our ability to determine masses comes from considering all the kinematic information in the event, including the missing momentum, in conjunction with the quadratic constraints that arise from the $Y$, $X$ and $N$ mass-shell conditions. Realistic missing momentum and lepton momenta uncertainties are included in the analysis.Comment: 41 pages, 14 figures, various clarifications and expanded discussion included in revised version that conforms to the version to be publishe

Test of Factorization Hypothesis from Exclusive Non-leptonic B decays

We investigate the possibility of testing factorization hypothesis in non-leptonic exclusive decays of B-meson. In particular, we considered the non factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+} (\pi^-, \rho^-) known as well-factorizable modes. By taking the ratios BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(\pi^-,\rho^-)), we found that under the present theoretical and experimental uncertainties there's no evidence for the breakdown of factorization description to heavy-heavy decays of the B meson.Comment: 11 pages; submitted to PR

Little Technicolor

Inspired by the AdS/CFT correspondence, we show that any G/H symmetry breaking pattern can be described by a simple two-site moose diagram. This construction trivially reproduces the CCWZ prescription in the context of Hidden Local Symmetry. We interpret this moose in a novel way to show that many little Higgs theories can emerge from ordinary chiral symmetry breaking in scaled-up QCD. We apply this reasoning to the simple group little Higgs to see that the same low energy degrees of freedom can arise from a variety of UV complete theories. We also show how models of holographic composite Higgs bosons can turn into brane-localized little technicolor theories by "integrating in" the IR brane.Comment: 26 pages, 2 figures; v2: references added; v3: added section on vacuum alignment to match JHEP versio