1748432
Dynamical dimension change in supercritical string theory
We study tree-level solutions to heterotic string theory in which the number of spacetime dimensions 10+n changes dynamically due to closed string tachyon condensation. Taking the large-n limit, we compute the amount by which the dilaton gradient changes during the condensation process. At leading order in n we find that the change in the invariant magnitude of the dilaton gradient compensates the change in spacelike central charge on the worldsheet, so that the total worldsheet central charges are equal at early and late times. This result supports our interpretation of the worldsheet theory as a CFT of critical central charge which describes a dynamical reduction in the total number of spacetime dimensions.
14174042
Gravity duals of Lifshitz-like fixed points
We find candidate macroscopic gravity duals for scale-invariant but non-Lorentz invariant fixed points, which do not have particle number as a conserved quantity. We compute two-point correlation functions which exhibit novel behavior relative to their AdS counterparts, and find holographic renormalization group flows to conformal field theories. Our theories are characterized by a dynamical critical exponent z, which governs the anisotropy between spatial and temporal scaling t {yields} {lambda}{sup z}t, x {yields} {lambda}x; we focus on the case with z = 2. Such theories describe multicritical points in certain magnetic materials and liquid crystals, and have been shown to arise at quantum critical points in toy models of the cuprate superconductors. This work can be considered a small step towards making useful dual descriptions of such critical points.
18223996
Beauty is attractive: Moduli trapping at enhanced symmetry points
We study quantum effects on moduli dynamics arising from the production of particles which are light at points of enhanced symmetry in moduli space. The resulting forces trap the moduli at these points. Moduli trapping occurs in time-dependent quantum field theory, as well as in systems of moving D-branes, where it leads the branes to combine into stacks. Trapping also occurs in the presence of gravity, though the range over which the moduli can roll is limited by Hubble friction. We observe that a scalar field trapped on a steep potential can induce a stage of acceleration of the universe, which we call trapped inflation. Moduli trapping ameliorates the cosmological moduli problem and may affect vacuum selection. In particular, rolling moduli are most powerfully attracted to the points of greatest symmetry. Given suitable assumptions about the dynamics of the very early universe, this effect might help to explain why among the plethora of possible vacuum states of string theory, we appear to live in one with a large number of (spontaneously broken) symmetries.
118578199
$Z_b(10610)$ and $Z_b(10650)$ structures produced by the initial single pion emission in the $\Upsilon(5S)$ decays
We propose an unique mechanism called {\it Initial Single Pion Emission} existing in the $\Upsilon(5S)$ decays, and further study the line shapes of $d\Gamma(\Upsilon(5S\to \Upsilon(nS)\pi^+\pi^-))/dm_{\Upsilon(nS)\pi^+}$ ($n=1,2,3$) and $d\Gamma(\Upsilon(5S\to h_b(mP)\pi^+\pi^-))/dm_{h_b(mP)\pi^+}$ ($m=1,2$). We find sharp structures around 10610 MeV and 10650 MeV in the obtained theoretical line shapes of $d\Gamma(\Upsilon(5S\to \Upsilon(nS)\pi^+\pi^-))/dm_{\Upsilon(nS)\pi^+}$ and $d\Gamma(\Upsilon(5S\to h_b(mP)\pi^+\pi^-))/dm_{h_b(mP)\pi^+}$ distributions, which could naturally correspond to the $Z_b(10610)$ and $Z_b(10650)$ structures newly observed by Belle.
119278047
Charged charmoniumlike state $Z_c(3900)^±$ via meson photoproduction
In this work, we explore the production of the newly observed charged charmoniumlike state $Z_c(3900)^\pm$ by the photoproduction process $\gamma p\to Z_c(3900)^+n$. Our numerical result indicates that the maximum of the calculated total cross section of $\gamma p\to Z_c(3900)^+n$ can reach up to the order of $0.1 \mu b$. Furthermore, the Dalitz plot analysis is performed by considering the Pomeron exchange as the background contribution. This analysis shows that the $Z_c(3900)^+$ signal can be distinguished from the background easily and the best energy window of searching for $Z_c(3900)^+$ is $\sqrt{s}\simeq7$ GeV, which is important information for further experimental study of $Z_c(3900)^+$ by meson photoproduction.
119232556
D-wave heavy-light mesons from QCD sum rules
We study the D-wave (c) over bars heavy meson doublets (1(-), 2(-)) and (2(-), 3(-)) using the method of QCD sum rule in the framework of heavy quark effective theory. Choosing the same threshold values.c around 2.7 Gev, we calculate the masses of the 1(-) and 3(-) states. They are m(D*s1) = 2.81 +/- 0.10 GeV and m(D*s3) = 2.85 +/- 0.08 GeV, consistent with the newly observed D*(s1)(2860) and D*(s3)(2860) states by LHCb. The masses of their 2-partners are calculated to be 2.82 +/- 0.10 and 2.81 +/- 0.08 GeV. The mass splittings within the same doublet are calculated to be m(Ds2) - m(Ds1) = 0.016 +/- 0.007 GeV and m(D*s3) - m(D's2) = 0.039 +/- 0.014 GeV.
118327948
Reducing theoretical uncertainties for exclusive Higgs-boson plus one-jet production at the LHC
We resum a class of large Sudakov logarithms affecting Higgs boson production in the exclusive one-jet bin at the LHC. We extend previous results by calculating the full one-loop soft function for this process, which extends the accuracy of the resummation to include the leading three logarithmic corrections at each order in the QCD coupling constant. We match this result to the next-to-leading order cross section and present a detailed numerical study assuming realistic LHC cuts. Careful attention is paid to the matching procedure, and to the theoretical uncertainties induced by residual scale variation. We find that the matched NLL'+ NLO cross section has significantly smaller uncertainties than the fixed-order result, and can be used to alleviate the theoretical errors hindering current Higgs analyses at the LHC.
104297811
Can the observed enhancement in the mass spectrum of p anti-p in J / psi ---> gamma p anti-p be interpreted by a possible p anti-p n d bound state