Spontaneous Twin Symmetry Breaking

We consider a twin Higgs scenario where the $Z_2$ twin symmetry is broken spontaneously, not explicitly. This scenario provides an interesting interpretation of the Higgs metastability in the standard model; the $SU(4)$ breaking scale $f$ is determined by the scale where the Higgs self quartic coupling flips its sign. However, for the misalignment of nonzero vacuum expectation values of the twin Higgs fields, parameter tuning of ${\cal O}(m_h^2/f^2)$ is required like explicit twin symmetry breaking scenarios. For the minimal model with the exact twin symmetry, $f$ is ${\cal O}$($10^{10}$ GeV), so the model is very unnatural. We point out that the tuning can be significantly reduced ($f\gtrsim 2.7$ TeV) if there are twin vector-like leptons with large Yukawa coupling to twin Higgs fields.Comment: 8 pages, 6 figures; published versio

Improved continuous magnetic separation assisted with advection flows in microfluidic channels

Department of Biomedical EngineeringMagnetophoretic separation efficiency is determined by a ratio of magnetic particles isolated by magnetic flux density gradients. Because the magnetic flux density gradients rapidly decrease as the distance from the magnetic source increases, the magetic particles which are placed far from the magnetic source are not separated. This is one of the key challenges to achieve high throughput magnetic separation device. Here, we report a magnetic separation device inducing specific fluid flow by patterning the obstacle arrays on the channel. We achieve highly augmented magnetic separation efficiency using chaotic convection flows induced by the slanted ridges in the channels. The asymmetric pressure gradients across the cross-section of the channel are induced by the slanted ridge arrays pattern in the channel, and then it occurs the spiral flows inside the microchannel. The spiral flows transfer the magnetic particles or biological cells integrated with magnetic particles toward the area with high magnetic flux density gradient where is close to the ferromagnetic nickel structure with magnet. With this suggested approach, over 91.68% of E. coli bound with magnetic nanoparticles (200 nm) in whole blood are successfully isolated at a flow rate up to 1.6 mL/h, in a single microfluidic channel, whereas conventional devices without advective rotational flows only isolated under 27.72%.ope

Spectral Decomposition of Missing Transverse Energy at Hadron Colliders

We propose a spectral decomposition to systematically extract information of dark matter at hadron colliders. The differential cross section of events with missing transverse energy (MET) can be expressed by a linear combination of basis functions. In the case of $s$-channel mediator models for dark matter particle production, basis functions are identified with the differential cross sections of sub-processes of virtual mediator and visible particle production while the coefficients of basis functions correspond to dark matter invariant mass distribution in the manner of the K\"all\'en-Lehmann spectral decomposition. For a given MET data set and mediator model, we show that one can differentiate a certain dark matter-mediator interaction from another through spectral decomposition.Comment: 6+4 pages, 6 figures, PRL versio