Momentum Dependent Vertices σγγ\sigma \gamma \gamma, σργ\sigma \rho \gamma and σρρ\sigma \rho \rho : The NJL Scalar Hidden by Chiral Symmetry

We calculate the momentum dependence of three particle vertices $\sigma \gamma \gamma$, $\sigma \rho \gamma$ and $\sigma \rho \rho$ in the context of a Nambu Jona Lasinio type model. We show how they influence the processes $\gamma \gamma \rightarrow \sigma \rightarrow \pi \pi$, $\rho \rightarrow \gamma \sigma$ and $\gamma \gamma \rightarrow \rho \rho$ and how chiral symmetry shadows the presence of the $\sigma$.Comment: 9 pages (latex), 5 figures available from the authors, preprint Coimbra 940506, IJS-TP-94/10, accepted for publication in Zeit. f. Physik

Renormalization-group analysis of the validity of staggered-fermion QCD with the fourth-root recipe

I develop a renormalization-group blocking framework for lattice QCD with staggered fermions. Under plausible, and testable, assumptions, I then argue that the fourth-root recipe used in numerical simulations is valid in the continuum limit. The taste-symmetry violating terms, which give rise to non-local effects in the fourth-root theory when the lattice spacing is non-zero, vanish in the continuum limit. A key role is played by reweighted theories that are local and renormalizable on the one hand, and that approximate the fourth-root theory better and better as the continuum limit is approached on the other hand.Comment: Minor corrections. Revtex, 58 page

Heavy-Light Semileptonic Decays in Staggered Chiral Perturbation Theory

We calculate the form factors for the semileptonic decays of heavy-light pseudoscalar mesons in partially quenched staggered chiral perturbation theory (\schpt), working to leading order in $1/m_Q$, where $m_Q$ is the heavy quark mass. We take the light meson in the final state to be a pseudoscalar corresponding to the exact chiral symmetry of staggered quarks. The treatment assumes the validity of the standard prescription for representing the staggered ``fourth root trick'' within \schpt by insertions of factors of 1/4 for each sea quark loop. Our calculation is based on an existing partially quenched continuum chiral perturbation theory calculation with degenerate sea quarks by Becirevic, Prelovsek and Zupan, which we generalize to the staggered (and non-degenerate) case. As a by-product, we obtain the continuum partially quenched results with non-degenerate sea quarks. We analyze the effects of non-leading chiral terms, and find a relation among the coefficients governing the analytic valence mass dependence at this order. Our results are useful in analyzing lattice computations of form factors $B\to\pi$ and $D\to K$ when the light quarks are simulated with the staggered action.Comment: 53 pages, 8 figures, v2: Minor correction to the section on finite volume effects, and typos fixed. Version to be published in Phys. Rev.

Toda Lattice Hierarchy and Zamolodchikov's Conjecture

In this letter, we show that certain Fredholm determinant $D(\lambda;t)$, introduced by Zamolodchikov in his study of 2D polymers, is a continuum limit of soliton solution for the Toda lattice hierarchy with 2-periodic reduction condition.Comment: 6 pages, LaTeX file, no figure

Identifikasi Variabel Penting Keandalan Bangunan Gedung Di Kota Serang

Peraturan bangunan gedung di Indonesia telah disahkan dan tertulis jelas pada Undang-Undang No.28 Tahun 2002 Tentang Bangunan Gedung. Undang-undang ini diamanatkan untuk diturunkan dalam bentuk Peraturan Daerah pada masing-masing kota/kabupaten yang ada di Indonesia. Sangat disayangkan hingga akhir tahun 2012 lalu, baru sekitar 21% kota/kabupaten di Indonesia yang memiliki Perda Bangunan Gedung. Salah satu daerah yang belum mengesahkan Peraturan Bangunan Gedungnya adalah Kota Serang. Hal ini sangat memprihatinkan mengingat Kota Serang merupakan kota pemerintahan yang merupakan ibukota dari Provinsi Banten. Untuk itu penelitian ini dilakukan untuk mengidentifikasi variabel penting bangunan gedung di Kota Serang. Untuk dapat memberikan rekomendasi yang tepat, perlu dilakukan studi mengenai bangunan gedung itu sendiri dan perlu juga dilakukan studi mengenai peraturan dan standar tentang bangunan gedung yang telah ada. Untuk studi mengenai bangunan gedung, diambil dari beberapa referensi yang relevan, sedangkan studi peraturan dan standar dilakukan dengan membedah peraturan bangunan gedung yang telah ada, seperti Undang-Undang No.28 Tahun 2012, Peraturan Pemerintah No.36 Tahun 2005, Perda DKI Jakarta No.7 Tahun 2010, serta Rancangan Peraturan Daerah (Raperda) Kota Tangerang Selatan Tentang Bangunan Gedung.Metode pengumpulan data pada kuisioner ini didapat dengan proses penyebaran kuisioner sebanyak dua kali. Hasil yang ingin dicapai dari penyebaran dua kuisioner ini adalah mengetahui faktor dan variabel yang berpengaruh pada suatu peraturan bangunan gedung di Kota Serang (Kuisioner 1), serta mengetahui tingkat pengaruh faktor dan variabel tersebut (Kuisioner 2). Dengan mengetahui faktor dan variabel beserta tingkat pengaruhnya, dapat ditarik sebuah kesimpulan mengenai hal-hal yang harus diatur dalam suatu peraturan bangunan gedung. Dengan mengetahui hal tersebut, kemudian rekomendasi yang tepat dapat diberikan kepada Kota Serang perihal Peraturan Bangunan Gedung

A Classification of random Dirac fermions

We present a detailed classification of random Dirac hamiltonians in two spatial dimensions based on the implementation of discrete symmetries. Our classification is slightly finer than that of random matrices, and contains thirteen classes. We also extend this classification to non-hermitian hamiltonians with and without Dirac structure.Comment: 15 pages, version2: typos in the table of classes are correcte

Two Photon Contribution to Polarization in K+→π+μ+μ−K^+ \rightarrow \pi^+ \mu^+ \mu^-

Short distance physics involving virtual top and charm quarks contributes to $\mu^+$ (and $\mu^-$) polarization in the decay $K^+ \rightarrow \pi^+ \mu^+ \mu^-$. Measurement of the parity violating asymmetry $(\Gamma_R - \Gamma_L)/(\Gamma_R + \Gamma_L)$, where $\Gamma_R$ and $\Gamma_L$ are the rates to produce right and left-handed $\mu^+$, may provide valuable information on the unitarity triangle. The parity violating asymmetry also gets a contribution from Feynman diagrams with two photon intermediate states. We estimate this two photon contribution to the asymmetry and discuss briefly the two photon contribution to time reversal odd asymmetries that involve both the $\mu^+$ and $\mu^-$ polarizations.Comment: (19 pages, 5 figures available on request. Uses phyzzx), CALT-68-1798, UCSD/PTH 92-2

The origin of the LMC stellar bar: clues from the SFH of the bar and inner disk

We discuss the origin of the LMC stellar bar by comparing the star formation histories (SFH) obtained from deep color-magnitude diagrams (CMDs) in the bar and in a number of fields in different directions within the inner disk. The CMDs, reaching the oldest main sequence turnoffs in these very crowded fields, have been obtained with VIMOS on the VLT in service mode, under very good seeing conditions. We show that the SFHs of all fields share the same patterns, with consistent variations of the star formation rate as a function of time in all of them. We therefore conclude that no specific event of star formation can be identified with the formation of the LMC bar, which instead likely formed from a redistribution of disk material that occurred when the LMC disk became bar unstable, and shared a common SFH with the inner disk thereafter. The strong similarity between the SFH of the center and edge of the bar rules out significant spatial variations of the SFH across the bar, which are predicted by scenarios of classic bar formation through buckling mechanisms.Comment: MNRAS Letters, accepte