SM Value Research Articles

Study of the heavy CP-even Higgs with mass 125 GeV in two-Higgs-doublet models at the LHC and ILC

We assume that the 125 GeV Higgs discovered at the LHC is the heavy CP-even Higgs of the two-Higgs-doublet models, and examine the parameter space in the Type-I, Type-II, Lepton-specific and Flipped models allowed by the latest Higgs signal data, the relevant experimental and theoretical constraints. Further, we show the projected limits on $\tan\beta$, $\sin(\beta-\alpha)$, $Hf\bar{f}$ and $HVV$ couplings from the future measurements of the 125 GeV Higgs at the LHC and ILC, including the LHC with integrated luminosity of 300 fb$^{-1}$ (LHC-300 fb$^{-1}$) and 3000 fb$^{-1}$ (LHC-3000 fb$^{-1}$) as well as the ILC at $\sqrt{s}=250$ GeV (ILC-250 GeV), $\sqrt{s}=500$ GeV (ILC-500 GeV) and $\sqrt{s}=1000$ GeV (ILC-1000 GeV). Assuming that the future Higgs signal data have no deviation from the SM expectation, the LHC-300 fb$^{-1}$, LHC-3000 fb$^{-1}$ and ILC-1000 GeV can exclude the wrong-sign Yukawa coupling regions of the Type-II, Flipped and Lepton-specific models at the $2\sigma$ level, respectively. The future experiments at the LHC and ILC will constrain the Higgs couplings to be very close to SM values, especially for the $HVV$ coupling.

Room temperature magnetocaloric effect and refrigerant capacitance in La0.7Sr0.3MnO3 nanotube arrays

High aspect ratio La0.7Sr0.3MnO3 nanotube (NT) arrays have been synthesized using nitrates based sol-gel precursor by nanoporous anodized aluminum oxide template assisted method. Their phase purity and microstructures were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Magnetocaloric effect (MCE) of as prepared NTs was investigated by means of field dependence magnetization measurements. Significant magnetic entropy change, −△SM = 1.6 J/kg K, and the refrigerant capacitance, RC = 69 J/kg, were achieved near the transition temperature at 315 K for 5 T. For comparison, a bulk sample was also prepared using the same precursor solution which gives a value of −△SM = 4.2 J/kg K and a RC = 165 J/kg. Though the bulk sample exhibits higher △SM value, the NTs present an expanded temperature dependence of −△SM curves that spread over a broad temperature range and assured to be appropriate for active magnetic refrigeration. The diminutive MCE observed in manganite NTs is explained by the increased influence of surface sites of nanograins which affect the structural phase transition occurred by external magnetic field due to the coupling between magnetism and the lattice in manganese perovskites. Our report paves the way for further investigation in 1D manganite nanostructured materials towards applications in such magnetic refrigeration technology or even on hyperthermia/drug delivery.

Improved sphaleron decoupling condition and the Higgs coupling constants in the real singlet-extended standard model

We improve the sphaleron decoupling condition in the real singlet-extended standard model. The sphaleron energy is obtained using the finite temperature one-loop effective potential with daisy resummation. For moderate values of the model parameters, the sphaleron decoupling condition is found to be $v_C/T_C>(1.1-1.2)$, where $T_C$ denotes a critical temperature and $v_C$ is the corresponding vacuum expectation value of the doublet Higgs field at $T_C$. We also investigate the deviation of the triple Higgs boson coupling from its standard model value in the region where the improved sphaleron decoupling condition is satisfied. As a result of the improvement, the deviation of the triple Higgs boson coupling gets more enhanced. In a typical case, if the Higgs couplings to the gauge bosons/fermions deviate from the SM values by about 3 (10)%, the deviation of the triple Higgs boson coupling can be as large as about 16 (50)%, which is about 4 (8)% larger than that based on the conventional criterion $v_C/T_C>1$.

Higgs precision measurements and flavor physics: a supersymmetric example

[Review for "Chinese Science Bulletin" and CEPC+SPPC Proposal] Rare decays in flavor physics often suffer from Helicity suppress and Loop suppress. Helicity flip is a direct consequence of chiral $U(3)$ symmetry breaking and electroweak symmetry breaking. The identical feature is also shared by the mass generation of SM fermions. In this review, we use MSSM as an example to illustrate an explicit connection between bottom Yukawa coupling and rare decay process of $b\to s\gamma$. We take a symmetry approach to study the common symmetry breaking in supersymmetric correction to bottom quark mass generation and $b\to s\gamma$. We show that Large Peccei-Quinn symmetry breaking effect and $R$-symmetry breaking effect required by $b\to s\gamma$ inevitably lead to significant reduction of bottom Yukawa ${y}_{b}$. To compromise the reduction in $b\bar{b}$, a new decay is also needed to keep the Higgs total width as the SM value.

The price of being SM-like in SUSY

We compute the tuning in supersymmetric models associated with the constraints from collider measurements of the Higgs couplings to fermions and gauge bosons. In supersymmetric models, a CP -even state with SM Higgs couplings mixes with additional, heavier CP -even states, causing deviations in the Higgs couplings from SM values. These deviations are reduced as the heavy states are decoupled with large soft masses, thereby exacerbating the tuning associated with the electroweak scale. This new source of tuning is different from that derived from collider limits on stops, gluinos and Higgsinos. It can be offset with large tan β in the MSSM, however this compensating effect is limited in the NMSSM with a large Higgs-singlet coupling due to restrictions on large tan β from electroweak precision tests. We derive a lower bound on this tuning and show that the level of precision of Higgs coupling measurements at the LHC will probe naturalness in the NMSSM at the few-percent level. This is comparable to the tuning derived from superpartner limits in models with a low messenger scale and split families. Instead the significant improvement in sensitivity of Higgs coupling measurements at the ILC will allow naturalness in these models to be constrained at the per-mille level, beyond any tuning derived from direct superpartner limits.

Enhanced Desorption of PAHs from Manufactured Gas Plant Soils Using Different Types of Surfactants

Surfactant enhanced remediation is thought to be an effective method for the remediation of soils polluted with hydrophobic organic compounds. Desorption of polycyclic aromatic hydrocarbons (PAHs) from an abandoned manufactured gas plant (MGP) soil was evaluated using four eluting agents including Triton X-100 (TX100), sodium dodecylbenzene sulfonate (SDBS), rhamnolipid water solution (RWS) and rhamnolipid fermentation broth (RFB). The weight solubilization ratios for acenaphthene and fluorene were in the order of TX100 > SDBS > RWS > RFB. The Sm value, which indicates the maximum amounts of surfactants adsorbed in the soil, was in the order of RWS > RFB > SDBS > TX100. By using 8 g L−1 of TX100, SDBS and RWS and 100% of RFB, the T-PAHs removal for the MGP soil contaminated with 207.86 mg T-PAHs kg−1 dry soil was 48.0%, 45.7%, 1.9%, and 8.6%, respectively, while that decreased to 41.6%, 37%, 0.38%, and 1.3% for the soil contaminated with 3 494.78 mg T-PAHs kg−1 dry soil. Only 8 g L−1 TX100 could remove all types of the 16 PAHs partly in the MGP soil, and the removal efficiencies of different PAHs ranged from 13% to 77.8%. The results of this study herein provide valuable information for the selection of TX100 surfactant for remediating PAH-contaminated soils in MGP.

LHC diphoton and Z+photon Higgs signals in the Higgs triplet model with Y = 0

We study the implications of the LHC diphoton and Z+photon Higgs signals on the Higgs triplet model with Y=0. We discuss three different scenarios: (i) the observed boson is the light Higgs boson $h$; (ii) it is the heavy Higgs boson $H$; (iii) the observed signal is from the almost degenerate $h$ and $H$. We find that the inclusive Higgs diphoton rates in the first two scenarios can be enhanced or suppressed compared to the SM value, which can respectively fit the ATLAS and CMS diphoton data within $1\sigma$ range. The inclusive $ZZ^*$ rates are suppressed, which are outside $1\sigma$ range of ATLAS data and within $1\sigma$ range of CMS data. Meanwhile, another CP-even Higgs boson production rate can be suppressed enough not to be observed at the collider. For the third scenario, the Higgs diphoton rate is suppressed, which is outside $1\sigma$ range of ATLAS data, and the $ZZ^*$ rate equals to SM value approximately. In addition, we find that the two rates of $h\to \gamma\gamma$ and $h\to Z\gamma$ have the positive correlations for the three scenarios.

Study on solubilization capability of various Gemini micelles in micellar-enhanced ultrafiltration of phenol-contaminated waters

A systematic study has been conducted to have an insight into the separation efficiency of phenol with the help of Gemini surfactants and conventional nonionic surfactant in their single and mixed systems using micellar-enhanced ultrafiltration (MEUF). A flat sheet membrane with a total effective area of 0.08 m2 and a molecular weight cut-off of 10 kDa, was selected in this investigate. The effects of feed component (surfactant concentration for single surfactant system and mixed ratio for mixed surfactant system) on solubilization and filtration efficiency were researched. Some related parameters were used to estimate the performance of various surfactant systems, such as distribution coefficient (D), the phenol concentration in micellar phase (Pm), the surfactant concentration in micellar phase (Sm), the micelle loading (Lm), and the equilibrium distribution constant (K). With the increase of feed surfactant concentration or the addition of nonionic surfactant, the degree of solubilization of phenol enhances, leading to the decrease of permeate concentration and the augment of retentate concentration. Consequently, D, Pm, and Sm increases. The addition of nonionic surfactant has positive effects to recounterbalance the interior structure and improve the micellar solubilization power for phenol. Both the single and mixed C12-2-16 systems have higher D, Pm, and Sm values than these of C12-2-12, due to the longer length alkyl chain and more optimized structure. Lm and K are the significant indicators for evaluating the effectiveness of dissolving phenol. Irreversible fouling was almost eliminated with a series of cleaning solution in a short time. There results from the laboratory-scale experiments could be very useful in selection of the suitable surfactant systems for raising efficiency and could serve as valuable guide for MEUF in industrial application.

331 models facing new b → sμ + μ − data

We investigate how the 331 models face new data on B_{s,d}->mu^+mu^- and B_d->K^*mu^+mu^- taking into account present constraints from Delta F=2 observables, low energy precision measurements, LEP-II and the LHC data. In these models new flavour violating interactions of ordinary quarks and leptons are dominated by a new heavy Z^prime gauge boson with the strength of the relevant couplings governed by four new parameters in the quark sector and the parameter beta. We study the implications of these models for beta=+-n/sqrt{3} with n=1,2,3. The case beta=-sqrt{3} leading to Landau singularities for M_{Z'}approx 4Tev can be ruled out when the present constraints on Z^prime couplings, in particular from LEP-II, are taken into account. For n=1,2 interesting results are found for M_{Z^prime}< 4Tev with largest NP effects for beta<0 in B_d->K^*mu^+mu^- and the ones in B_{s,d}->mu^+mu^- for beta>0. As Re(C_9^NP) can reach the values -0.8 and -0.4 for n=2 and n=1, respectively the B_d-> K^*mu^+mu^- anomalies can be softened with the size depending on Delta M_s/(Delta M_s)_SM and the CP-asymmetry S_{psiphi}. A correlation between Re(C_9^NP) and BR(B_s->mu^+mu^-), identified for beta<0, implies for negative Re(C_9^NP) uniquely suppression of BR(B_s->mu^+mu^-) relative to its SM value which is favoured by the data. In turn also S_{psiphi}< S_{psiphi}^SM is favoured having dominantly opposite sign to S_{psiphi}^SM. We find that the absence of B_d-> K^*mu^+mu^- anomalies in the future data and confirmation of the suppression of BR(B_s->mu^+mu^-) relative to its SM value would favour beta=1/sqrt{3} and M_{Z'}approx 3Tev. Assuming lepton universality, we find an upper bound |C_9^NP|<1.1(1.4) from LEP-II data for all Z' models with only left-handed flavour violating couplings to quarks when NP contributions to Delta M_s at the level of 10%(15%) are allowed.

Higgcision in the two-Higgs doublet models

We perform global fits to general two-Higgs doublet models (2HDMs) with generalized couplings using the most updated data from ATLAS, CMS, and Tevatron. We include both scenarios with CP-conserving and CP-violating couplings. By relaxing the requirement on the discrete symmetries that are often imposed on the Yukawa couplings, we try to see which of the 2HDMs is preferred. We found that (i) Higgcision in 2HDMs can be performed efficiently by using only 4 parameters including the charged Higgs contributions to the Higgs couplings to two photons, (ii) the differences among various types of 2HDMs are very small with respect to the chi-square fits, (iii) tan β is constrained to be small, (iv) the p-values for various fits in 2HDMs are worse than that of the standard model. Finally, we put emphasis on our findings that future precision measurements of the Higgs coupling to the scalar top-quark bilinear $ \left( {C_u^S} \right) $ and tan β may endow us with the discriminating power among various types of 2HDMs especially when $ C_u^S $ deviates from its SM value 1.

Higgs-pair production and measurement of the triscalar coupling at [formula omitted

We simulate the measurement of the triscalar Higgs coupling at LHC(8,14) via pair production of h (125 GeV). We find that the most promising hh final state is bb¯γγ. We account for deviations of the triscalar coupling from its SM value and study the effects of this coupling on the hh cross-section and distributions with cut-based and multivariate methods. Our fit to the hh production matrix element at LHC(14) with 3 ab−1 yields a 30% uncertainty on this coupling in the SM and a range of 20–60% uncertainties for non-SM values.

Left-handed Z′ and Z FCNC quark couplings facing new b → sμ + μ − data

In view of the recent improved data on B_{s,d}->mu^+ mu^- and B_d->K^*mu^+mu^- we revisit two simple NP scenarios in which new FCNC currents in b->s mu^+ mu^- transitions are mediated either entirely by a neutral heavy gauge boson Z' with purely LH complex couplings Delta_L^{qb}(Z') (q=d,s) and couplings to muons Delta_A^{mu mu}(Z') and Delta_V^{mu mu}(Z') or the SM Z boson with LH complex couplings Delta_L^{qb}(Z). We demonstrate how these couplings can be determined by future Delta F=2 and b->s mu^+ mu^- observables. The correlations between various observables can test these NP scenarios. We present the results as functions of Delta M_q/Delta M_q^SM, S_{psi phi} and S_{psi K_S} which should be precisely determined in this decade. We calculate the violation of the CMFV relation between BR(B_{s,d}-> mu^+ mu^-) and Delta M_{s,d} in these scenarios. We find that the data on B_{s,d}->mu^+ mu^- from CMS and LHCb can be reproduced in both scenarios but in the case of Z, Delta M_s and S_{psi phi} have to be very close to their SM values. As far as B_d->K^*mu^+mu^- anomalies are concerned the Z' scenario can significantly soften these anomalies while the Z boson fails because of the small vector coupling to muons. We also point out that recent proposals of explaining these anomalies with the help of a real Wilson coefficient C^NP_9 implies uniquely an enhancement of Delta M_s with respect to its SM value, while a complex C^NP_9 allows for both enhancement and suppression of Delta M_s and simultaneously novel CP-violating effects. We also discuss briefly scenarios in which the Z' boson has RH FCNC couplings. In this context we point out a number of correlations between angular observables measured in B_d->K^*mu^+ mu^- that arise in the absence of new CP-violating phases in scenarios with only LH or RH couplings or scenarios in which LH and RH couplings are equal to each other or differ by sign.

Pair production of a 125 GeV Higgs boson in MSSM and NMSSM at the ILC

In this work we investigate the Higgs pair production in the MSSM and NMSSM at the photon-photon collision of the ILC. We consider various experimental constraints and scan over the parameter space of the MSSM and NMSSM. Then we calculate the cross section of Higgs pair production in the allowed parameter space and compare the results with the predictions in the SM. We find that the large enhancement of the cross section in the MSSM is mainly due to the contributions from the loops mediated by the stau, while in the NMSSM it is mainly due to the contributions from the top-squark loops. For light $m_{\tilde{\tau}_1}$ and large $\mu\tan\beta$, the production rate can be enhanced by a factor of 18 in the MSSM (relative to the SM prediction). And for a large trilinear soft breaking parameter $A_t$ and a moderately light top-squark, it can also be enhanced by a factor of 2 in the NMSSM. Moreover, we also calculate the $\chi^2$ values with the LHC Higgs data and display the results for the parameter space with $\chi^2$ better than the SM value.

Preparation method and thermal properties of samarium and europium-doped alumino-phosphate glasses

Abstract The present work investigates alumino-phosphate glasses from Li2O–BaO–Al2O3–La2O3–P2O5 system containing Sm3+ and Eu3+ ions, prepared by two different ways: a wet raw materials mixing route followed by evaporation and melt-quenching, and by remelting of shards. The linear thermal expansion coefficient measured by dilatometry is identical for both rare-earth-doped phosphate glasses. Comparatively to undoped phosphate glass the linear thermal expansion coefficient increases with 2 × 10−7 K−1 when dopants are added. The characteristic temperatures very slowly decrease but can be considered constant with atomic weight, atomic number and f electrons number of the doping ions in the case of Tg (vitreous transition temperature) and Tsr (high annealing temperature) but slowly increase in the case of Tir (low annealing temperature–strain point) and very slowly increase, being practically constant in the case of TD (dilatometric softening temperature). Comparatively to undoped phosphate glass the characteristic temperatures of Sm and Eu-doped glasses present lower values. The higher values of electrical conductance for both doped glasses, comparatively to usual soda-lime-silicate glass, indicate a slightly reduced stability against water. The viscosity measurements, showed a quasi-linear variation with temperature the mean square deviation (R2) being ranged between 0.872% and 0.996%. The viscosity of doped glasses comparatively to the undoped one is lower at the same temperature. Thermogravimetric analysis did not show notable mass change for any of doped samples. DSC curves for both rare-earth-doped phosphate glasses, as bulk and powdered samples, showed Tg values in the range 435–450 °C. Bulk samples exhibited a very weak exothermic peak at about 685 °C, while powdered samples showed two weak exothermic peaks at about 555 °C and 685 °C due to devitrification of the glasses. Using designed melting and annealing programs, the doped glasses were improved regarding bubbles and cords content and strain elimination.

The Effects of Simplest Little Higgs Model on the Spin Correlations in the Top Quark Pair Production at the LHC and ILC

In the simplest little Higgs model (SLH), we study the spin correlations in the top quark pair production at the LHC and ILC. We find that the SLH always suppresses the tt̄ spin correlations compared to the SM values. At the LHC, the suppression can be over 10% for mz′ < 750 GeV. The SLH prediction value is outside the 1σ range of the experimental data from ATLAS, and within 1σ range of the experimental data from CMS. At the ILC, the SLH can sizably suppress the tt̄ spin correlation for mz′ approaching the center-of-mass energy √s. For example, the maximal suppression can reach −22.5%, −14.5%, and −9.5% for √s = 500 GeV, 800 GeV, and 1000 GeV, respectively. Therefore, the tt̄ spin correlation at the ILC can be a sensitive probe for the SLH.

The SM extension with color-octet scalars: diphoton enhancement and global fit of LHC Higgs data

In light of the significant progress of the LHC to determine the properties of the Higgs boson, we investigate the capability of the Manohar-Wise model in explaining the Higgs data. This model extends the SM by one family of color-octet and isospin-doublet scalars, and it can sizably alter the coupling strengths of the Higgs boson with gluons and photons. We first examine the current constraints on the model, which are from unitarity, the LHC searches for the scalars and the electroweak precision data (EWPD).In implementing the unitarity constraint, we use the properties of the SU(3) group to simplify the calculation. Then in the allowed parameter space we perform a fit of the model, using the latest ATLAS and CMS data, respectively. We find that the Manohar-Wise model is able to explain the data with \chi^2 significantly smaller than the SM value. We also find that the current Higgs data, especially the ATLAS data, are very powerful in further constraining the parameter space of the model. In particular, in order to explain the diphoton enhancement reported by the ATLAS collaboration, the sign of the hgg coupling is usually opposite to that in the SM.

Influence of solidification rate and heat treatment on magnetic refrigerant properties of melt spun Ni51Mn34In14Si1 ribbons

Influence of solidification rate and heat treatment on magnetic and magnetic refrigerant properties such as magnetic entropy change (ΔSM) and refrigerant capacity (RC) of melt spun ribbons of Ni51Mn34In14Si1 alloy is reported. The characteristic temperatures and magnetic refrigerant properties of as-spun ribbons decreased with increasing solidification rate. Higher solidification rate achieved by higher wheel speed yielded ribbons with partially ordered B2 austenite phase instead of the ordered L21 austenite structure. Structural properties improved and the characteristic temperatures increased upon heat treatment of the as-spun ribbons at elevated temperatures. Considerable enhancement in ΔSM and RC values were observed in 823K heat treated ribbons obtained at lower solidification rate. A good combination of ∆SM (=14.1Jkg−1K−1) and RC (=37.3Jkg−1) values were obtained at reasonably low magnetic field change of 1.2T for the ribbons melt spun at a wheel speed of 16m/s followed by annealing at 823K for 1800s.

Particle-antiparticle mixing, CP violation and rare K and B decays in a minimal theory of fermion masses

We present a detailed study of Delta F=2 observables and of rare K^+(K_L) and B_{s,d} meson decays in a "Minimal Theory of Fermion Masses" (MTFM). In this theory Yukawa couplings are generated through the mixing with heavy vectorlike (VF) fermions. This implies corrections to the SM quark couplings to W, Z and Higgs so that FCNC processes receive contributions from tree level Z and Higgs exchanges and W bosons couple to right-handed quarks. In a particular version of this model in which the Yukawa matrix lambda^D in the heavy down fermion sector is unitary, lambda^U =1 and M = M_{VF} is fixed, only three real and positive definite parameters describe New Physics (NP) contributions to all Delta F=2 and Delta F=1 observables in K and B_{s,d} systems once the known quark masses and the CKM matrix are correctly reproduced. For M>1 TeV NP contributions to B_{s,d}^0- bar{B}_{s,d}^0 mixings are found to be very small. While in principle NP contributions to epsilon_K and Delta F=1 processes could be large, the correlation between epsilon_K and K_L->mu^+ mu^- eliminates basically NP contributions to epsilon_K and right-handed current contributions to Delta F=1 FCNC observables. We find CMFV structure in B_{s,d} decays with BR(B_{s,d}->mu^+ mu^-) uniquely enhanced for M=3 TeV by at least 35% and almost up to a factor of two over their SM values. Also BR(K^+->pi^+ bar{nu} nu) and BR(K_L->pi^0 bar{nu} nu)$ are uniquely enhanced by similar amount but the correlation between them differs from the CMFV one. We emphasize various correlations between K and B_{s,d} decays that could test this scenario. The model favours gamma=68{\deg}, |V_{ub}|=0.0037, S_{psi K_S}=0.72, S_{psi phi}=0.04 and 4.2*10^-9<BR(B_s->mu^+ mu^-)<5.0*10^-9 for M=3-4 TeV.

Temperature stimulated changes in potato and bean sprouts

The potato and bean sprouts were tested using dynamic mechanical analysis (DMA), in air with 90% humidity between 30 and 90°C. Temperature plots of storage (SM i.e. elastic) and loss (LM i.e. inelastic) moduli were obtained. The SM and LM values were the basis for the calculation of the loss tangent (LT), the parameter expressing the ratio of inelastic to elastic parenchyma toughness. As expected, the tissue toughness decreased with increasing temperature. For both moduli, the characteristic temperature area with temperature slope minimum was observed – it was termed the negative peak on the temperature slope plots or separation point. It was shown that the negative peak was related to an increase in the inelastic part of the tissue toughness. These changes were interpreted as a consequence of pore protein denaturation followed by changes of the internal stresses inside the parenchyma cells.

Liberating Higgs couplings in supersymmetry

In the MSSM, the Higgs couplings to down-type quarks and leptons, normalized with respect to their corresponding Standard Model values, coincide at tree-level and this degeneracy is only slightly broken at the quantum level. Motivated by the latest results of the Higgs searches at the LHC and Tevatron, we explore the possibility of disentangling these couplings from each other by considering a scenario in which supersymmetry is broken spontaneously at a low scale. In such a scenario, all the Higgs couplings, except the ones to the Z and W bosons, receive tree level corrections that depend on the MSSM soft parameters. In particular, the corrections to the Yukawa couplings depend on the A-term soft parameter for the corresponding fermion, allowing for the freedom to break their usual relations, even in the MSSM decoupling limit. We highlight the main features of this scenario in terms of a benchmark point for which the normalized Higgs coupling to the tau leptons is depleted, the coupling to photons is enhanced, while all the other Higgs couplings, including the one to the bottom quarks, are close to their corresponding SM values. We also discuss the experimental bounds arising mainly from di-tau searches and comment on the discovery/exclusion prospects at the LHC.