Note on new interesting baryon channels to measure the photon polarization in b -> s gamma

At LHC a large number of b-flavored baryons will be produced. In this note we propose new baryon modes to determine the photon helicity of the penguin transition $b \to s \gamma$. The decay $\Lambda_b \to \Lambda \gamma$ has the drawback that the $\Lambda$, being neutral and long-lived, will escape detection most of the time. To overcome this difficulty, transitions of the type $\Lambda_b \to \Lambda^{*} \gamma$ have been proposed, where $\Lambda^{*}$ denotes an excited state decaying strongly within the detector into the clean mode $p K^-$. The doublet $\Xi_b$, that decays weakly, has a number of good features. The charged baryon $\Xi_b^-$ will decay into the mode $\Xi^- \gamma$, where the ground state hyperon $\Xi^-$, although it will decay most of the time outside the detector, can be detected because it is charged. We consider also the decay of $\Xi_b$ into $\Xi^{*} \gamma$, where a higher mass state $\Xi^{*}$ can decay strongly within the detector. We point out that the initial transverse polarization of $\Xi_b$ has to be known in all cases. To determine this parameter through the transition $\Xi_b \to J/\Psi\ \Xi$, we distinguish between different cases, and underline that in some situations one needs {\it theoretical input} on the asymmetry parameter $\alpha_{\Xi_b}$ of the primary decay. {\it A fortiori} the same considerations apply to the case of the $\Lambda_b$

Fenomena Pelanggaran Kode Etik Jurnalistik Pasal 12 Tahun 2008 Di Media Online Manado Post

What is the ethic codes of journalistic, is not understand fully by the young journalists. They lack of understanding on plagiarism in particular. There are two cases remarkable to note for young journalists. Firstly, on the function of the ethic codes for journalists, and secondly, on the affectivity of carrying out the ethic code for journalists. Therefore, the young journalists has to learn and practices the ethic codes

Isospin dependence of 6He+p optical potential and the symmetry energy

A consistent folding analysis of the elastic p(6He,6He)p scattering and charge exchange p(6He,6Li*)n reaction data measured at Elab=41.6A MeV has been performed within the coupled channels formalism. We have used the isovector coupling to link the isospin dependence of 6He+p optical potential to the cross section of p(6He,6Li*)n reaction exciting the 0+ isobaric analog state (IAS) at 3.563 MeV in 6Li. Based on these results and the Hartree-Fock calculation of asymmetric nuclear matter using the same isospin-dependent effective nucleon-nucleon interaction, we were able to confirm that the most realistic value of the symmetry energy Esym is around 31 MeV. Our analysis has also shown that the measured charge exchange p(6He,6Li*)n data are quite sensitive to the halo tail of the 6He density used in the folding calculation and the IAS of 6Li is likely to have a halo structure similar to that established for the ground state of 6He.Comment: Accepted for publication in Phys. Rev.

Analisa Performansi Sistem Komunikasi Single-Input Multiple-Output Pada Lingkungan Indoor Menggunakan WARP

Dalam sistem komunikasi nirkabel, salah satu permasalahan yang dihadapi adalah multipath fading. Hal ini mengakibatkan level daya yang bervariasi pada penerima sehingga terjadi outage ketika mengalami fading. Dalam lingkungan indoor, hal ini lebih sering terjadi karena hampir tidak ada line-of-sight antara pemancar dan penerima. Efek kanal multipath bisa diatasi dengan sistem komunikasi SIMO (Single-Input Multiple-Output). Sinyal yang diterima diolah menggunakan beberapa metode seperti Selection dan Maximal Ratio Combining dengan jumlah antena di penerima lebih dari satu. Implementasi juga bisa dilakukan pada WARP (Wireless Open-Access Research Platform) yang merupakan salah satu jenis SDR (Software Defined Radio). Modul tersebut digunakan sebagai pemancar dan penerima pada pengukuran kualitas performansi SIMO pada lingkungan indoor dengan metode-metode combining. Hasil unjuk kerja dibandingkan terhadap sistem SISO (Single-Input Single-Output). Hasil dari implementasi dan pengukuran pada penelitian ini menunjukan bahwa, dalam lingkungan indoor pada kondisi tertentu, sistem SIMO dengan metode selection combining memiliki diversity gain 2.3–2.5 dB, sedangkan maximal ratio combining memiliki diversity gain 2.5–4.6 dB lebih baik daripada SISO pada kondisi BER

The WAY theorem and the quantum resource theory of asymmetry

The WAY theorem establishes an important constraint that conservation laws impose on quantum mechanical measurements. We formulate the WAY theorem in the broader context of resource theories, where one is constrained to a subset of quantum mechanical operations described by a symmetry group. Establishing connections with the theory of quantum state discrimination we obtain optimal unitaries describing the measurement of arbitrary observables, explain how prior information can permit perfect measurements that circumvent the WAY constraint, and provide a framework that establishes a natural ordering on measurement apparatuses through a decomposition into asymmetry and charge subsystems.Comment: 11 pages, 3 figure

Determination of the CP Violating Phase γ\gamma by a Sum Over Common Decay Modes to BsB_s and Bˉs\bar{B}_s

To help the difficult determination of the angle $\gamma$ of the unitarity triangle, Aleksan, Dunietz and Kayser have proposed the modes of the type $K^-D^+_s$, common to $B_s$ and $\bar{B}_s$. We point out that it is possible to gain in statistics by a sum over all modes with ground state mesons in the final state, i.e. $K^-D^+_s$, $K^{*-}D_+^s$, $K^-D^{*+}_s$, $K^{*-}D^{*+}_s$. The delicate point is the relative phase of these different contributions to the dilution factor $D$ of the time-dependent asymmetry. Each contribution to $D$ is proportional to a product $F^{cb}$ $F^{ub}$ $f_{D_s}$ $f_K$ where $F$ denotes form factors and $f$ decay constants. Within a definite phase convention, lattice calculations do not show any change in sign when extrapolating to light quarks the form factors and decay constants. Then, we can show that all modes contribute constructively to the dilution factor, except the $P$-wave $K^{*-}D^{*+}_s$, which is small. Quark model arguments based on wave function overlaps also confirm this stability in sign. By summing over all these modes we find a gain of a factor 6 in statistics relatively to $K^-D^+_s$. The dilution factor for the sum $D_{tot}$ is remarkably stable for theoretical schemes that are not in very strong conflict with data on $B \to \psi K(K^*)$ or extrapolated from semileptonic charm form factors, giving $D_{tot} \geq 0.6$, always close to $D(K^- D^+_s)$.Comment: 22 pages, LPTHE Orsay 94/03, DAPNIA/SPP/94-2