24,763 research outputs found

### Heavy QQ(bar) "Fireball" Annihilation to Multiple Vector Bosons

Drawing analogy of replacing the nucleon by heavy chiral quark $Q$, the pion
by Goldstone boson $G$, and $\pi NN$ coupling by $GQQ$ coupling, we construct a
statistical model for $Q\bar Q \to nG$ annihilation, i.e. into $n$ longitudinal
weak bosons. This analogy is becoming prescient since the LHC direct bound $m_Q
> 611$ GeV implies strong Yukawa coupling. Taking $m_Q \in (1, 2)$ TeV, the
mean number $$ ranges from 6 to over 10, with negligible two or three
boson production. With individual $t'$ or $b'$ decays suppressed either by
phase space or quark mixing, and given the strong Yukawa coupling, $Q\bar Q\to
nV_L$ is the likely outcome for very heavy $Q\bar Q$ production at the LHC.Comment: 4 pages, 1 figur

### Search for Bottom Counterparts of X(3872) and Y(4260) via $\pi^+\pi^-\Upsilon$

The X(3872) and Y(4260), both discovered in $\pi^+\pi^- J/\psi$ mode, are
rather unusual: $X_c\equiv X(3872)$ is very narrow, while $Y_c \equiv Y(4260)$
has large $Y_c\to \pi^+\pi^-J/\psi$ width. Many models for their composition
have been suggested, but perhaps discovering their bottom counterparts could
shed much light on the issue. The narrow state, $X_b$ may be searched for at
the Tevatron via $p\bar p \to \pi^+\pi^-\Upsilon + X$, with the LHC much more
promising. The state $Y_b$ can be searched for at B factories via radiative
return $e^+e^- \to \gamma_{\rm ISR} + \pi^+\pi^-\Upsilon$ on $\Upsilon(5S)$, or
by $e^+e^- \to \pi^+\pi^-\Upsilon$ direct scan.Comment: 4 pages, no figures, presented at ICHEP 200

### ElectroWeak BaryoGenesis via Top Transport

We study electroweak baryogenesis driven by the top quark in two Higgs
doublet model that allows flavor-changing neutral Higgs couplings. Taking Higgs
sector couplings and the additional top Yukawa coupling $\rho_{tt}$ to be
$\mathcal{O}$(1), one naturally has first order electroweak phase transition
and sufficient $CP$ violation to fuel the cosmic baryon asymmetry. Even if
$\rho_{tt}$ vanishes, the favor-changing coupling $\rho_{tc}$ can still achieve
baryogenesis. Phenomenological consequences such as $t\to ch$, $\tau \to
\mu\gamma$, electron electric dipole moment, $h\to\gamma\gamma$, and $hhh$
coupling are discussed. The extra scalars $H^0$, $A^0$ and $H^\pm$ are sub-TeV
in mass, and can be searched for at the LHC.Comment: 5 pages, 3 figures, to appear in proceedings of EPS-HEP2017 held July
2017 in Venic

### Effects of New Physics on CP Violation in B Decays

We discuss two models with 1 extra CP phase in $b\leftrightarrow s$
transition. The CP phase $\arg (V_{t^\prime s}V_{t^\prime b})$ with fourth
generations, previously ignored, could impact on $b\to s\ell^+\ell^-$, $\Delta
m_{B_s}$ and $\sin2\Phi_{B_s}$, but does not affect EM and strong penguins.
With SUSY at TeV scale, a right-handed ``$\widetilde{sb}_{1}$'' squark can be
driven light by flavor mixing. It does not affect $b\to s\ell^+\ell^-$, but can
generate $S_{\phi K_S} < 0$ while giving $S_{\eta^\prime K_S} \sim
\sin2\Phi_{B_d} \cong0.74$. $B_s$ mixing and $\sin2\Phi_{B_s}$ would likely be
large, and $S_{K_S\pi^0\gamma}\neq 0$ in $B^0\to K^{*0}\gamma$ is promising.Comment: 3 pages, 3 figures. Talk presented at EPS2003 Conference, Aachen,
Germany, July 200

### (Vector) Glueballs and Charmonium Decay Revisited

From the $0^{++}$ glueball candidate we argue that the $1^{--}$ glueball $O$
to be near in mass to $J/\psi$. This is supported by the recent null search for
$\psi^\prime \to \rho\pi, K^*\bar K$, while absence of distortion in the energy
scan of $J/\psi \to \rho\pi$ indicates that $\Gamma_O \gg \Gamma_{J/\psi}$. $O$
may also play a role in the OZI violating $\bar p p \to \phi\gamma, \phi\pi$
production puzzle.Comment: 3 pages, latex (with sprocl.sty), no figures; talk presented at
DPF96, Minneapolis, August 10-15, 199

### $P_5'$ Anomaly for Top: $tZ'$ Production at LHC

The $P_5'$ anomaly uncovered by the LHCb experiment in $B \to K^*\mu\mu$
angular observables has motivated a possible $Z'$ boson that couples to
left-handed $b \to s$ transitions, where a model would be gauged $L_\mu -
L_\tau$ symmetry, but direct search for such a $Z'$ is not promising. Less
constrained is an analogous $Z'$ coupling to right-handed $t \to c$
transitions. Motivated by this, we study $cg \to tZ'$ associated production at
LHC, both for a generic model, and in $L_\mu - L_\tau$ with a vector-like U
quark. We also study $c\bar c \to Z'$ production that exists within the model.
Both processes can be probed already with LHC Run 2 data, all the way up to the
HL-LHC with discovery potential.Comment: 6 pages, 8 figures. Talk presented at the APS Division of Particles
and Fields Meeting (DPF 2017), July 31-August 4, 2017, Fermilab. C17073

### On the gauge features of gravity on a Lie algebroid structure

We present the geometric formulation of gravity based on the mathematical
structure of a Lie Algebroid. We show that this framework provides the
geometrical setting to describe the gauge propriety of gravity.Comment: We corrected a mistake in Eq (8). This equation is only part of the
review presented in the introduction and does not effect the rest of the
pape

### Possibility of Large FSI Phases in Light of $B\to K\pi$ & $\pi\pi$ Data

After briefly reviewing how data indicated that factorization seems to work
in observed two body charmless modes, {\it if one takes \gamma \gtap
90^\circ}, we point out that the $K^0\pi^0$ mode seems too large. This and
other hints suggest that perhaps not only $\gamma$ is large, but rescattering
phase $\delta$ could be sizable as well.Comment: 3 pages, 1 eps figure included. To appear in Proceedings of
ICHEP2000, Osaka, Japan, 27 July - 2 August 200

### Strongly Enhanced Gilbert Damping in 3d Transition Metal Ferromagnet Monolayers in Contact with Topological Insulator Bi2Se3

Engineering Gilbert damping of ferromagnetic metal films is of great
importance to exploit and design spintronic devices that are operated with an
ultrahigh speed. Based on scattering theory of Gilbert damping, we extend the
torque method originally used in studies of magnetocrystalline anisotropy to
theoretically determine Gilbert dampings of ferromagnetic metals. This method
is utilized to investigate Gilbert dampings of 3d transition metal ferromagnet
iron, cobalt and nickel monolayers that are contacted by the prototypical
topological insulator Bi2Se3. Amazingly, we find that their Gilbert dampings
are strongly enhanced by about one order in magnitude, compared with dampings
of their bulks and free-standing monolayers, owing to the strong spin-orbit
coupling of Bi2Se3. Our work provides an attractive route to tailoring Gilbert
damping of ferromagnetic metallic films by putting them in contact with
topological insulators.Comment: 5 figures; 18 page

### On processing development for fabrication of fiber reinforced composite, part 2

Fiber-reinforced composite laminates are used in many aerospace and automobile applications. The magnitudes and durations of the cure temperature and the cure pressure applied during the curing process have significant consequences for the performance of the finished product. The objective of this study is to exploit the potential of applying the optimization technique to the cure cycle design. Using the compression molding of a filled polyester sheet molding compound (SMC) as an example, a unified Computer Aided Design (CAD) methodology, consisting of three uncoupled modules, (i.e., optimization, analysis and sensitivity calculations), is developed to systematically generate optimal cure cycle designs. Various optimization formulations for the cure cycle design are investigated. The uniformities in the distributions of the temperature and the degree with those resulting from conventional isothermal processing conditions with pre-warmed platens. Recommendations with regards to further research in the computerization of the cure cycle design are also addressed

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