Effective string description of confining flux tubes

We review the current knowledge about the theoretical foundations of the effective string theory for confining flux tubes and the comparison of the predictions to pure gauge lattice data. A concise presentation of the effective string theory is provided, incorporating recent developments. We summarize the predictions for the spectrum and the profile/width of the flux tube and their comparison to lattice data. The review closes with a short summary of open questions for future research.Comment: 21 pages, 8 figures, Contribution to IJMPA special issue "Lattice gauge theory beyond QCD

Tinjauan Yuridis Hubungan Fungsional Antara Penyidik Dan Penuntut Umum Dalam Proses Pemeriksaan Perkara Pidana

Kitab Undang-Undang Hukum Acara Pidana mengatur antara lain tugas dan wewenang masing-masing penegak hukum didalam pemeriksaan perkara tindak pidana. Tugas penyidikan dilakukan oleh pihak Kepolisian sedangkan tugas penuntutan terhadap pelaku tindak pidana dilakukan oleh pihak Kejaksaan. Walaupun tugas kepolisian dan kejaksaan berbeda dan terpisah satu denga yang lainnya, tetapi diantara mereka tetap ada hubungan yang bersifat fungsional. Hal ini diseabkan pemeriksaan tindak pidana itu berproses yang dimulai dari penyidikan, penuntutan dan berakhir degan pemeriksaan di pengadilan. Penyidik dilakukan oleh kepolisian demi untuk kepentigan penuntutan atau dengan kata lain penuntutan tidak bisa dilakukan kalau tidak ada hasil penyidikan yang dilakukan oleh kepolisian. Hubungan fungsional antara penyidik dengan penuntut umum dapat diketahui dengan adanya ketentuan yang diatur dalam pasal 109 dan 110 KUHAP. Pasal 109 KUHAP mengatur tentang penyidik yang telah memulai penyidikannya memberitahukan hal tersebut kpada penuntut umum. Kalaupun penyidik menghentikan penyidikaanya maka hal itu juga diberitahukan kepada penuntut umum. Pasal 110 KUHAP mengatur yaitu dalam hal penyidikan telah selesai melakukan penyidikan, penyidik wajib segera menyerahkan berkas perkara kepada penuntut umum. Dalam hal penutut umum berpendapat bahwa hasil penyidikan belum lenkap, maka penuntut umum segerah mengembalikan berkas tersebut kepada penyidik disertai petunjuk untuk di lengka

Antiscreening of the Ampere force in QED and QCD plasmas

The static forces between electric charges and currents are modified at the loop level by the presence of a plasma. While electric charges are screened, currents are not. The effective coupling constant at long distances is enhanced in both cases as compared to the vacuum, and by different amounts, a clear sign that Lorentz symmetry is broken. We investigate these effects quantitatively, first in a QED plasma and secondly using non-perturbative simulations of QCD with two light degenerate flavors of quarks.Comment: 17 pages, 8 figure

The effects of spatially distributed ionisation sources on the temperature structure of HII region

Spatially resolved studies of star forming regions show that the assumption of spherical geometry is not realistic in most cases, with a major complication posed by the gas being ionised by multiple non-centrally located stars or star clusters. We try to isolate the effects of multiple non-centrally located stars on the temperature and ionisation structure of HII regions, via the construction of 3D photoionisation models using the 3D Monte Carlo photoionisation code MOCASSIN. We find that the true temperature fluctuations due to the stellar distribution (as opposed to the large-scale temperature gradients due to other gas properties) are small in all cases and not a significant cause of error in metallicity studies. Strong emission lines from HII regions are often used to study the metallicity of star-forming regions. We compare integrated emission line spectra from our models and quantify any systematic errors caused by the simplifying assumption of a single, central location for all ionising sources. We find that the dependence of the metallicity indicators on the ionisation parameter causes a clear bias, due to the fact that models with a fully distributed configuration of stars always display lower ionisation parameters than their fully concentrated counterparts. The errors found imply that the geometrical distribution of ionisation sources may partly account for the large scatter in metallicities derived using model-calibrated empirical methods.Comment: 13 pages, 6 figures, Accepted by MNRA

Calculation of the pion electromagnetic form factor from lattice QCD

We present a lattice calculation of the vector form factor of the pion for two flavours of non-perturbatively O(a) improved Wilson fermions. For the measurements we utilise the CLS ensembles which include various lattice spacings and pion masses down to about 250 MeV. To obtain a fine momentum resolution near zero momentum transfer (q^2) partially twisted boundary conditions are employed using several twist angles. Due to the fine resolution around q^2=0 we are able to determine the slope of the form factor and, in turn, extract the charge radius of the pion without any model dependence. The results for the form factor and the charge radius are then compared to chiral perturbation theory and phenomenological models which are used to extrapolate the results to the physical point.Comment: 4 pages, 4 figures, talk presented at Hadron 2011: 14th International Conference on Hadron Spectroscopy, Munich, German