A probe of the Radion-Higgs mixing in the Randall-Sundrum model at e^+ e^- colliders

In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by the effective electroweak scale. A novel feature of the existence of gravity-scalar mixing would be a sizable three-point vertex among the KK graviton, Higgs and radion. We study this vertex in the process e^+ e^- -> h phi, which is allowed only with a non-zero radion-Higgs mixing. It is shown that the angular distribution is a unique characteristic of the exchange of massive spin-2 gravitons, and the total cross section at the future e^+ e^- collider is big enough to cover a large portion of the parameter space where the LEP/LEP II data cannot constrain.Comment: 14pages, RevTeX, 5 figure

Associated production of a single heavy T-quark in the littlest and simplest little Higgs models

The colored SU(2)-singlet heavy T-quark is one of the most crucial ingredients in little Higgs models, which is introduced to cancel the largest contribution of the SM top quark to the Higgs boson mass at one-loop level. In two representative little Higgs models, the littlest Higgs model and the SU(3) simplest Higgs model, we comprehensively study the single heavy T-quark production at Large Hadron Collider (LHC). After presenting the possibility of relatively light (~500 GeV) T-quark in the simplest little Higgs model, we consider all the relevant processes, the 2->2 process of qb->q'T, the 2->3 process of qg->q'Tb, the s-channel process of q bar(q)'->T bar{b}, and the gluon fusion process of gg->T bar{t}. We found that the 2->3 process can be quite important, as its cross section is about 30% of the 2->2 one and it is dominant in high p_T distributions. The s-channel and the gluon fusion processes also show distinctive features in spite of their suppressed cross sections. In the gluon fusion process of the simplest little Higgs model, for example, the pseudo-scalar contribution is rather dominant over the Higgs contribution for relatively light M_T.Comment: 27 pages, using RevTeX; references adde

Convergence of the all-time supremum of a L\'evy process in the heavy-traffic regime

In this paper we derive a technique of obtaining limit theorems for suprema of L\'evy processes from their random walk counterparts. For each $a>0$, let $\{Y^{(a)}_n:n\ge 1\}$ be a sequence of independent and identically distributed random variables and $\{X^{(a)}_t:t\ge 0\}$ be a L\'evy processes such that $X_1^{(a)}\stackrel{d}{=} Y_1^{(a)}$, $\mathbb E X_1^{(a)}<0$ and $\mathbb E X_1^{(a)}\uparrow0$ as $a\downarrow0$. Let $S^{(a)}_n=\sum_{k=1}^n Y^{(a)}_k$. Then, under some mild assumptions, $\Delta(a)\max_{n\ge 0} S_n^{(a)}\stackrel{d}{\to} R\iff\Delta(a)\sup_{t\ge 0} X^{(a)}_t\stackrel{d}{\to} R$, for some random variable $R$ and some function $\Delta(\cdot)$. We utilize this result to present a number of limit theorems for suprema of L\'evy processes in the heavy-traffic regime

Deriving the ideal ore texture for microwave treatment of metalliferous ores

High power density microwave treatments on metalliferous ores have historically been shown to reduce ore competency prior to beneficiation at economically feasible energy inputs. However, the relationship between mineralogical textural features and the extent of the microwave-induced fracturing had previously been limited to qualitative descriptions or simplistic two-phase numerical models, which could not account for the complex mineral assemblages in real ores. In this paper, mineralogy, grain size, dissemination, textural consistency and mineral associations were determined for 13 commercially exploited nickel, copper and lead-zinc ores using a Mineral Liberation Analyser (MLA). The ores were subjected to high power density microwave treatments at up to 25kW in a single mode cavity with microwave energy inputs of approximately 0.5-10kWh/t, and the subsequent reductions in ore competency were measured by the Point Load Test. The ores that demonstrated the greatest reductions in strength typically contained between approximately 2%wt to 20%wt of highly microwave-absorbing minerals, with a native grain size d50 greater than approximately 500µm, constrained by hard matrix minerals such as quartz and feldspar. Texturally consistent ores with a high proportion of amenable textures also demonstrated the highest average reductions in strength. These findings support the qualitative descriptions and numerical modelling results available in the literature and provide a baseline for selecting likely candidate ores for microwave treatments in the future

Increasing the grind size for effective liberation and flotation of a porphyry copper ore by microwave treatment

In this paper, mineralogy, grain size, dissemination, textural consistency and mineral associations were determined for a commercially exploited porphyry copper ore using a Mineral Liberation Analyser (MLA). The ore was subjected to high power density microwave treatments in a single mode cavity at 15 kW and approximately 2 kW h/t. The untreated and microwave-treated samples were subsequently milled to two grind sizes near the nominal plant grind size and a size-by-liberation analysis performed. The analysis revealed that equivalent liberation could be obtained at a grind size approximately 50–60 μm coarser than the nominal plant grind due to the microwave treatment. Flotation testing indicated that an increase in copper recovery of approximately 1% could be achieved, or that a grind size increase of approximately 30 μm may potentially yield equivalent copper recovery due to the microwave-enhanced liberation observed. However, statistical analyses demonstrated that it is difficult to attain confidence in recovery increases of approximately 1% even when conducting batch flotation tests in triplicate. The ore under investigation had previously been shown to produce only modest average reductions in strength (∼8%) under similar microwave treatment conditions due to a prevalence of many unfavourable textures. However, the preferential association of copper minerals with a hard matrix mineral (quartz) and a hard microwave-absorbent mineral (pyrite) resulted in a significant change in liberation behaviour

Effect of selection on ancestry: an exactly soluble case and its phenomenological generalization

We consider a family of models describing the evolution under selection of a population whose dynamics can be related to the propagation of noisy traveling waves. For one particular model, that we shall call the exponential model, the properties of the traveling wave front can be calculated exactly, as well as the statistics of the genealogy of the population. One striking result is that, for this particular model, the genealogical trees have the same statistics as the trees of replicas in the Parisi mean-field theory of spin glasses. We also find that in the exponential model, the coalescence times along these trees grow like the logarithm of the population size. A phenomenological picture of the propagation of wave fronts that we introduced in a previous work, as well as our numerical data, suggest that these statistics remain valid for a larger class of models, while the coalescence times grow like the cube of the logarithm of the population size.Comment: 26 page

Cosmic positron and antiproton constraints on the gauge-Higgs Dark Matter

We calculate the cosmic ray positron and antiproton spectra of a gauge-Higgs dark matter candidate in a warped five-dimensional $SO(5) \times U(1)$ gauge-Higgs unification model. The stability of the gauge-Higgs boson is guaranteed by the H parity under which only the Higgs boson is odd at low energy. The 4-point vertices of HHW^+W^- and HHZZ, allowed by H parity conservation, have the same magnitude as in the standard model, which yields efficient annihilation rate for $m_H > m_W$. The most dominant annihilation channel is $H H \to W^+ W^-$ followed by the subsequent decays of the $W$ bosons into positrons or quarks, which undergo fragmentation into antiproton. Comparing with the observed positron and antiproton spectra with the PAMALA and Fermi/LAT, we found that the Higgs boson mass cannot be larger than 90 GeV, in order not to overrun the observations. Together with the constraint on not overclosing the Universe, the valid range of the dark matter mass is restricted to 70-90 GeV.Comment: 13 pages, 3 figure